Between 2015 and 2016, Lucy Letby harmed babies in her care with the intention of killing them. The means of harm varied: causing air embolus by introducing air via intravenous lines; forcing air into the abdomen via nasogastric tubes; force feeding milk; poisoning by administering insulin; physical trauma. She alone was present on the unit at the time of all the deaths and deteriorations.
Following an internal review of the deaths, and the suspension of the applicant from nursing duties, the police began an investigation in May 2017. Letby was convicted in August 2023 of seven counts of murder and seven of attempted murder of infants at the neonatal unit at the Countess of Chester Hospital. She was acquitted on two further counts of attempted murder and the jury was unable to agree on a further six counts of attempted murder. The Court of Appeal rejected Letby’s application for leave to appeal against her convictions after the credibility of Prosecution’s lead expert, Dewi Evans‘ testimony was affirmed.
Evans, a retired paediatrician, was asked to review initially 33 sets of clinical records involving death or deterioration of an infant on the unit and then a further 28 sets of records.
He was retained to provide an opinion on the cause of the collapse of each baby. Lucy Letby’s barrister Mark McDonald told a news conference in London that Evans, had allegedly altered his view about how the babies died. Evans added: “Mark McDonald’s observations regarding my evidence is unsubstantiated, unfounded, inaccurate. Evans said the only change in his evidence related to the date a child referred to as Baby C died but insisted it was a simple error by the prosecution.
Pediatrics Expert Witness
Dewi Evans provides expert medical advice regarding clinical issues where child abuse is suspected or where there are allegations of clinical negligence. He has prepared reports for the Court for over 25 years and has given evidence in court in Wales, England, Ireland and Northern Ireland.
He was appointed a consultant paediatrician in 1980; he had been trained in neonatology although, at the time, this was not a specific sub-specialty, hence he was never a consultant neonatologist; he set up a neonatal intensive care service in Swansea; he designed a new neonatal unit in 1990.
“The defense will argue that Evans is not a reliable expert, and all the convictions are not safe,” McDonald said. He said: “Remarkably, Evans has now changed his mind on the cause of death of three of the babies: Baby C, Baby I and Baby P.
The Court was told that one of Letby’s victims, Baby C weighed just 800g (1lb 12oz) when he was born in early June 2015, but despite that, medics recorded that he was in a “good condition” and stable.
He was being kept in the highest priority section of the neonatal unit, but on the night of 13 June, he suddenly stopped breathing.
The Court heard Letby, who was the designated nurse in a different section but was present when Baby C collapsed, caused the issue at about 23:15 BST by inserting air into his stomach via a nasogastric tube.
Medics failed to revive him and he was pronounced dead at 05:58 on 14 June
According to McDonald, Evans had “revised his opinion in relation to Baby C” and had written a new report which he had given to police months ago. But, he added “despite numerous requests” the prosecution had “yet to give this report to the defense”.
Evans previously told BBC that Baby C was likely to have died due to “a combination of air and milk” pumped via the nasogastric tube into the stomach, which differed from what he had said in Court when he only mentioned air.
He told the BBC it had led him “to review the events leading up to Infant C’s collapse and death” and thought it “more likely” that it was an injection of air into the bloodstream, although he stressed either would be “inflicted injury”.
Key Takeaway:
Mark McDonald accused Dewi Evans of retracting his earlier statements about how the babies died. Evans allegedly revised his opinion regarding Baby C but failed to provide the defense with his updated report.
However, Evans said he was “surprised how little he changed his mind” while working on the case.
Please refer to the blog previously published about this case:
For over 10 years, Fisher-Price sold a product called the Rock ‘n Play Sleeper (RnP). The Plaintiff, Ameena Brown, argued that the defective design of the RnP was to blame because her infant son, A.B., had died from sleeping in it. The dangers of this inclined sleeper product were widely debated in this case.
It all started when A.B.’s mother, Plaintiff Ameena Brown, was gifted a secondhand Rock ‘n Play for A.B. During naptime and overnight sleep, Ameena would place A.B. supine in the RnP, which she kept in the living room.
On January 15, 2018, the day before A.B.’s death, there was nothing out of the ordinary about A.B.’s health or demeanor. At approximately 6:00 AM the next morning, Ameena awoke and went to check on A.B. A.B. was found dead in the Rock ‘n Play.
Erin Mannen’s investigation found, among other things, that inclined sleepers can cause infants to roll from their back to their stomach or side and that once the infant is in this compromised position, the infant is at a heightened risk of suffocation. Defendants asserted that Mannen “ignored” studies commissioned by Fisher-Price that reached results contrary to her own and moved to exclude Mannen’s opinions.
Biomechanical Engineering Expert Witness
Erin Mannen is a biomechanical engineer who specializes in infant biomechanics and is the Director of the Boise Applied Biomechanics of Infants (BABI) Laboratory. She has published several peer-reviewed papers on the subject and won the American Society of Biomechanics Early Career Achievement Award for this work.
It is noteworthy that A.B. suffered from several medical problems resulting from his premature birth, including hypertonicity. A.B. also suffered from developmental delays. Brown placed A.B., clothed and swaddled, on his back in the RnP. Sometime during the night, A.B. came to be on his side. When Brown awoke, she discovered A.B. “stiff.” Emergency services were unable to revive A.B.
Mannen’s report considered the effect inclined sleep products have on an infant’s ability to roll from their back, an infant’s ability to correct a compromised position after rolling, the rate at which an infant attempting to correct its position would fatigue, and the consequences those compromising positions would have on an infant’s breathing.
Mannen Qualifies As An Expert On Biomechanics
Mannen’s testimony would also show the use of an inclined sleeper makes it harder for an infant to correct a compromising position. Mannen’s report also touched on the topic of rebreathing. Defendants contended that: (1) Mannen did not qualify as a medical doctor and cannot give medical opinions; (2) Mannen failed to account for the specific conditions present in this case, thus preventing any of the findings of her studies from being applied to the instant set of facts; and (3) Mannen’s studies did not support her conclusion and did not utilize reliable methodology.
The Court found that her knowledge, skill, experience, training, and education meet the level of qualification required under Daubert. In other words, Defendants did not meaningfully contest Mannen’s qualifications as an expert on biomechanics.
The specific causation testimony that Defendants objected to concerned the following conclusions: (1) rebreathing and its impact; (2) the design of the RnP facilitated A.B. turning his head and coming into contact with the soft mesh siding of the RnP; (3) A.B. died from either positional asphyxiation or suffocation; and (4) the RnP caused A.B.’s death. Defendants argued that Mannen’s lack of medical expertise precluded her from opining on the topics of rebreathing and A.B.’s cause of death. Defendants further asserted a blanket objection to “any other specific causation opinion.” Plaintiffs contended that Mannen does not offer any medical opinions, and all of her opinions regarding specific causation are based on her expertise in biomechanics.
Mannen’s Causation Testimony Is Generally Admissible
Defendants argued Mannen’s opinion on rebreathing should be excluded because she does not qualify as a pulmonologist and improperly relied on the report of another expert, Michael D. Leshner.
The Court held that Mannen’s lack of qualification as pulmonologist does not necessarily preclude her from opining on rebreathing, as an expert may rely on the reports of other experts to help form the basis of their own opinion.
Her opinion, formed based on her analysis of Leshner’s data, states “in a side-lying or a 90-degree head turn situation, [ ] an infant would experience significantly increased CO2 inhalation simply due to the design of the product.”
Mannen synthesized that data generated by Leshner’s report; considered her peer-reviewed research, her inspection of the product, and her own expertise in biomechanics; and concluded that the environment created by placing an infant in the RnP creates “a dangerous CO2 rebreathing and/or suffocation scenario.”
Due to the deficiencies in that other Leshner’s methodology, the Court held that Mannen may not rely on Leshner’s report.
The Court struck Mannen’s conclusion that “in a side-lying or a 90-degree head turn situation, an infant would experience significantly increased CO2 inhalation simply due to the design of the product” because it was calculated with the data from Leshner’s unreliable methodology.
The Court concluded that Mannen’s other conclusions regarding whether an infant would be at risk for rebreathing in the RnP were based on her examination of an RnP, her peer-reviewed research, and her expertise as a biomechanical engineer. Accordingly, Mannen’s testimony regarding rebreathing that does not rely on Leshner’s methodology is admissible.
Mannen’s Studies Sufficiently Fit The Instant Facts and are Admissible
Mannen’s various studies examined infants and their muscle activity when placed at various inclines. Mannen studied healthy infants wearing only a diaper.
On the night of his death, A.B.’s limbs were restricted by a swaddle and layers of clothing. A.B. also suffered from hypertonicity, a condition of excessive muscle tone that may limit an infant’s range of motion.
Defendants argued that these variations between the facts surrounding A.B.’s death and Mannen’s studies prevented Mannen’s opinion from possessing the requisite fit to be admissible.
Mannen concedes she did not study infants who were clothed or swaddled, or any infants suffering from hypertonicity. Nevertheless, her studies and report explain how an infant previously unable to roll on his own may have been able to roll because of the incline present in the RnP. Further, her report explains how once A.B. rolled to his side, he may have been unable to reposition and would have struggled to breathe correctly. The Court held that these explanations are relevant to the ultimate issue in this case—how the RnP’s design may have contributed to A.B.’s death.
Defendants posited that Mannen, relied on tests that did not involve persons with the victim’s characteristics. However, the Court found that Mannen had a basis on which to assert that her conclusions regarding the risk of rolling for infants not suffering from hypertonicity could be applied to A.B. Mannen, provides an “ordinary infant” standard and applies that standard to an infant less susceptible to injury; thus, there is no additional susceptibility to injury that would invalidate her conclusions as applied to A.B.
Mannen’s Studies Employed Reliable Methodology
Defendants argued Mannen’s “easier-to-roll” hypothesis is unsupported by the studies she cites.
As to Mannen’s conclusion that a side-facing infant would come into contact with the side of the RnP, leading to an increased risk of suffocation, Defendants argued that Mannen’s demonstration using a soccer ball in place of an infant “is not based on any recognized methodology for examining potential respiratory compromises.”
Mannen’s studies—the 2019 Consumer Product Safety Commission study (the “CPSC study”) and the studies identified as “Wang 2020” and “Wang 2021″—examined the effects of sleep surfaces on an infant’s muscle activity to determine “if the design of inclined sleep products impacted suffocation risk from a movement and body position perspective.”
While conducting the CPSC study, Mannen studied ten infants placed on sleeping surfaces with increasing levels of incline. Mannen and her team monitored body position and muscle activity. Mannen subsequently conducted a similar study involving 15 infants, and published those results in peer-reviewed journals as the Wang 2020 and Wang 2021 studies.
Those studies found that infants placed in inclined sleepers experience different muscle activity and body position compared to infants on flat surfaces. Mannen opined that those differences make it easier for an infant to roll from supine to prone—a roll that necessitates the infant being on his side if only for a brief moment—which places the infant at greater risk of maneuvering into a compromised position.
The studies were not intended to measure the frequency infants rolled when placed in inclined sleepers, but rather the inclined sleeper’s biomechanical effect on an infant’s ability to roll.
Held
The Court found that Mannen explained her methodology; addressed what each finding means generally and in relation to A.B.’s case; considered potential errors within the studies; and subjected both the Wang 2020 and Wang 2021 studies to peer review.
Moreover, Defendants appeared to misinterpret Mannen’s use of a soccer ball in her opinion.
Defendants contend “that test, however, which involved manipulating a soccer ball by hand in a [RnP], is not based on any recognized methodology for examining potential respiratory compromises, and the test appears to have used a [RnP] model with an additional pad…” Mannen, however, did not perform a test with a soccer ball. Rather, she used the soccer ball in a series of pictures to demonstrate how something approximately the size of an infant’s head would be positioned after a 90-degree turn.
Mannen’s use of a soccer ball as a stand-in for an infant’s head appeared reasonable to the Court. As the soccer ball’s utilization was illustrative rather than substantive, that illustration is admissible.
The Court concluded that many of Defendants’ challenges relate to credibility and may be dealt with during cross-examination of Mannen. It was decided that Mannen may testify regarding rebreathing only to the extent that she relies on peer-reviewed studies or her own expertise; accordingly, Mannen’s rebreathing testimony may not touch on Leshner’s Report or any conclusions reliant on his methodology.
Key Takeaway:
Mannen utilized her expertise in biomechanics to opine on: (1) how the RnP design allowed A.B. to turn onto his side; (2) how the RnP design made it more difficult for A.B. to correct his position once on his side; (3) the risk of rebreathing and suffocation created by the RnP; and (4) the increased fatigue caused by an infant unable to correct his position. None of those opinions offer a medical opinion. All those opinions are either the direct product of Mannen’s expertise, or her reasonable reliance on the reports of other experts. Thus, Mannen’s lack of medical expertise does not preclude her from offering those opinions.
The Boppy Newborn Lounger (“BNL”) was on the market for nearly sixteen years, and during that time, Boppy sold over 3.3 million BNLs. Boppy’s warnings and marketing made clear that the BNL was intended to give caregivers a place to lay infants down for supervised awake time only, but never for sleeping. As with any product, there were risks associated with improper use, against which Boppy warned and for which Boppy provided instructions concerning safe use.
On October 2, 2020, Plaintiff Danielle Clark swaddled her infant daughter (“D.B.”) in a blanket that was loosely wrapped around D.B.’s head, but not covering her face. D.B. was then placed “mainly on her side” and in the center of the BNL, which was sitting on the couch. Around 10:30 or 11:00 p.m., Clark fell asleep with her head on the side of the Boppy pillow. When Clark awoke approximately three to four hours later, she found her daughter unresponsive. The decedent was proclaimed dead, and according to the coroner, the cause was “probable asphyxia in the setting of co-sleeping and soft bedding.”
Plaintiffs alleged that the tragic death of their infant was caused by the BNL. Plaintiffs’ purported expert witness, Dr. Erin Mannen opined that “the design of the Boppy Newborn Lounger resulted in a dangerous biomechanical position that explains the death of [D.B.].” Dr. Ian Noy, also retained by the Plaintiffs, opined that the BNL’s warnings were inadequate.
Boppy filed motions to exclude the opinions provided by Erin Mannen and Ian Noy.
Human Factors Expert Witness
Ian Noy has a Ph.D. and M.S. in industrial engineering from the University of Toronto. He is a distinguished human factors and ergonomics consultant and forensic expert with extensive background in innovative and applied safety research, industrial engineering, behavioral sciences, and science management.
Erin M. Mannen earned a Ph.D. in Mechanical Engineering from the University of Kansas in 2014, completed a Postdoctoral Fellowship in the Center for Orthopaedic Biomechanics within the Department of Mechanical and Materials Engineering at the University of Denver in 2017, and has been researching biomechanics for over 14 years.
She is currently employed full-time as an assistant professor in the Mechanical and Biomedical Engineering Department at Boise State University in Boise, Idaho.
Boppy has moved to exclude the report of Plaintiffs’ expert witness, Ian Noy. Most of Boppy’s challenges do not relate to Noy’s qualifications or the relevance of his opinions, but rather, the reliability of his methodology. Specifically, Boppy takes issue with the following: (1) his failure to supply an alternative warning; (2) his reliance on the American National Standard Institute’s (“ANSI”) safety standards; (3) his failure to consider evidence regarding Clark’s refusal to follow the BNL’s warnings; and (4) his opinions about the design of the BNL.
His failure to supply an alternative warning
Boppy argued that an expert testifying on the inadequacy of a product’s warning is required to draft an adequate alternative warning. In the absence of a proposed alternative, Boppy argued, Noy’s opinions are unreliable.
Here, Noy was made personally aware of the label’s content through examining the BNL at issue. After examining the BNL and consulting a myriad of other materials, Noy highlighted alleged design deficiencies in the BNL’s safety alert signs on the product and its carrying case.
Noy appeared to suggest that, for example, the alternative proposed warning would include a safety label with no busy background, the font would be larger, there would be a distinction made between suffocation hazard and positional asphyxia hazard, there would be a description provided as to the nature and severity of hazards, and there would be a more effective message prohibiting “chin-on-chest” and providing contrasting symbols for “chin-on-chest” and “chin-off-chest” positions.
The Court found that “it would be simplistic to view [Noy’s] failure to ‘draft’ an alternative warning as being fatal to his opinion,” in light of the reasoning gleaned from his report and his expertise in human factors engineering.
His reliance on the American National Standard Institute’s (“ANSI”) safety standards
Boppy also challenged Noy’s reliance on standards from the American National Standards Institute (“ANSI”). According to Boppy, there is no ANSI standard that applies to the BNL or any baby lounging products.
It is noteworthy that Noy’s report summarizes ANSI Z535’s key requirements, and uses those requirements to outline the deficiencies in BNL’s warning label. According to the Court, this is not a situation where an expert is attempting to substitute scientific methodology for their personal observations.
Boppy also challenged Noy’s reliance on ANSI standards as a substitute for user testing.
The Court held that Noy’s opinions are not unreliable just because his report offered a comparative analysis based on ANSI standards, rather than results from user testing on the BNL’s warnings. While having expert testimony on this point would certainly aid Plaintiffs in proving causation, it is not essential for Daubert purposes.
His failure to consider evidence regarding Clark’s refusal to follow the BNL’s warnings
Boppy argued that Noy’s opinion is unreliable because he failed to consider evidence regarding Clark’s failure to follow the BNL’s warnings. The Court is unconvinced. In his deposition, Noy stated that Clark’s deposition was made available to him when he generated his expert report. Additionally, Noy confirmed that he knew Clark did not read the BNL’s labels.
His opinions about the design of the BNL
Boppy contended that Noy’s “report is littered with statements” that offer opinions about the BNL’s design, a topic which Noy is not qualified to speak on.
Boppy specifically takes issue with Noy’s statements about the hazard control hierarchy. According to Noy, the hazard control hierarchy is “a widely accepted process for eliminating or mitigating hazards through prioritized intervention strategies.”
As a human factors expert, the Court held that Noy can incorporate the hazard control hierarchy, a theory “[d]eveloped within the fields of safety and human factors,” into his expert report. Moreover, Noy can acknowledge that, for example, Boppy did not explore design alternatives and that Boppy did not conduct studies to inform safe product design, without opining on the biomechanical or related mechanism design defects in the BNL.
Mannen’s Report
Boppy filed a motion to exclude Erin Mannen’s expert report, which relates to the alleged design defects of the BNL. Boppy argued that Mannen (1) failed to consider the material facts of this case, (2) her opinions violate Rule 26, (3) she is not qualified to opine on cause of death, and (4) her opinion fails to account for alternative causes.
She failed to consider the material facts of this case
According to Boppy, Mannen failed to consider the facts and circumstances surrounding D.B.’s death. It is true that Mannen did not review Clark’s deposition before writing her report. Mannen did, however, consider Plaintiff’s Complaint, the autopsy report, photos of the reenactment of the incident, and the coroners file which contained the Howard County Police report.
Mannen explained that even taking into consideration the unsafe sleeping practices exercised by Clark, the BNL’s defective design was a substantial factor in D.B.’s death.
Boppy also takes issue with Mannen’s report being premised on an infant’s “ideal body position” in the product, when here, D.B. was placed on her side. When confronted with this discrepancy, Mannen explained that she “understand[s] that there was a blanket, and . . . that the baby was partially on her side, but that [did not] change the fact that even in an ideal body position, [she had] identified all these hazards in the [BNL].”
Mannen believes that there are inherent hazards in the BNL’s design, even if there is no misuse of the product or unsafe sleeping practices employed. The Court held that Mannen’s opinions are not deprived of a sound factual basis just because her opinion hones the BNL’s alleged inherent design flaws.
Her Opinions Violate Rule 26
According to Boppy, Mannen’s report should be excluded under Rule 26 because she has not shared information about the underlying incidents, products, and manufacturers included in the 2019 and 2022 U.S. Consumer Product Safety Commission (“CPSC”) studies her report relies on. In her report, Mannen concluded that, “[b]ecause of the similarities in the designs of inclined sleep products and the Boppy Newborn Lounger Pillow products . . . the concepts from our published in vivo biomechanics studies can be applied to the Boppy Newborn Lounger Pillow.” This is problematic, Boppy argued, because Mannen has refused to disclose the products involved in the studies. With the products left unidentified, Boppy states that it is “left to simply take her word for it,” that the unidentified products are similar to the BNL.
While Mannen cannot disclose the “incidents, products, and manufacturers” in her previous studies, the 2022 CPSC study provides photos of the sample pillows that were studied, and descriptions of the sample pillows, including their shape, mass, overall diameter or height and length, tube circumference or width, and thickness, as well as their cover and filler material. Albeit the 2019 CPSC study does not similarly provide photos of the fourteen inclined sleep products that were evaluated. However, Mannen’s report summarizes the sample measurements and characteristics of the products.
Thus, Boppy is not simply left to take Mannen’s word for it—Boppy has within its possession sufficient information to challenge Mannen’s assertion that the sample products are functionally similar to the BNL. The Court held that Boppy can surely critique Mannen’s opinions and attempt to distinguish the sample products tested in the 2019 and 2022 studies from the BNL on cross-examination. But exclusion of her testimony under Rule 26(a) is not appropriate in this case.
She is not qualified to opine on cause of death
Boppy also contended that Mannen’s report offers an opinion on D.B.’s cause of death.
Boppy asserts that by stating that “the design of the Newborn Lounger Pillow resulted in a dangerous biomechanical position that is capable of causing suffocation and/or positional asphyxia, like in the death of [D.B.],” Mannen impliedly offered a medical causation opinion.
As a biomechanical expert, the Court held that Mannen can attest to the design deficiencies in the BNL she believes contributed to D.B. rolling and suffocating.
Her opinion fails to account for alternative causes
Boppy expressed its dissatisfaction with Mannen’s failure to consider alternative causes—namely, the blanket, the side-lying, co-sleeping, and misuse of the BNL on the couch. In her rebuttal report, Mannen addressed the foregoing biomechanical problems that Boppy’s expert states played a role in D.B.’s death and offers her dissent.
These alleged contributors to D.B.’s ultimate suffocation certainly may prove problematic for Plaintiffs. That said, the Court held that Boppy can press Mannen on the extent to which these alleged biomechanical problems contributed to D.B.’s movement and ultimate suffocation at trial.
Held
The Court denied Plaintiffs’ motion to exclude the opinions provided by Dr. Ian Noy.
The Court denied Plaintiffs’ motion to exclude the opinions provided by Dr. Erin Mannen.
Key Takeaway:
The Daubert inquiry is a flexible one. Where, as here, an expert’s qualifications are clear and their methodology is sound, “helpful, legitimate expert testimony reaches the jury.”
Boppy’s qualms with Noy and Mannen’s opinion will no doubt be addressed on cross-examination.
Between 2015 and 2016, Lucy Letby harmed babies in her care with the intention of killing them. The means of harm varied: causing air embolus by introducing air via intravenous lines; forcing air into the abdomen via nasogastric tubes; force feeding milk; poisoning by administering insulin; physical trauma. She alone was present on the unit at the time of all the deaths and deteriorations.
Following an internal review of the deaths, and the suspension of the applicant from nursing duties, the police began an investigation in May 2017. Letby was convicted in August 2023 of seven counts of murder and seven of attempted murder of infants at the neonatal unit at the Countess of Chester Hospital. She was acquitted on two further counts of attempted murder and the jury was unable to agree on a further six counts of attempted murder. The Court of Appeal rejected Letby’s application for leave to appeal against her convictions after the credibility of Prosecution’s lead expert, Dewi Evans‘ testimony was affirmed.
Evans, a retired paediatrician, was asked to review initially 33 sets of clinical records involving death or deterioration of an infant on the unit and then a further 28 sets of records.
He was asked to provide an opinion on the cause of the collapse of each baby. As the lead expert during the investigation, he advised the police to seek further expertise from the fields of histopathology; paediatric radiology; paediatric haematology; paediatric endocrinology; paediatric neuroradiology and paediatric surgery.
Pediatrics Expert Witness
Dewi Evans provides expert medical advice regarding clinical issues where child abuse is suspected or where there are allegations of clinical negligence. He has prepared reports for the Court for over 25 years and has given evidence in court in Wales, England, Ireland and Northern Ireland.
He was appointed a consultant paediatrician in 1980; he had been trained in neonatology although, at the time, this was not a specific sub-specialty, hence he was never a consultant neonatologist; he set up a neonatal intensive care service in Swansea; he designed a new neonatal unit in 1990.
On appeal, Letby argued that Evans’ evidence should have been excluded from the jury’s consideration because he was not a neonatologist; he had not been in full time practice since 2009; most of his current work was purely as an expert witness; he could not be considered sufficiently independent because he had been part of the original investigation; his evidence was not sufficiently reliable to be admitted; he had been the subject of previous adverse judicial comment.
The Court, however, found him to be a “highly experienced consultant paediatrician” with “decades of clinical hands-on experience with neonates”. Moreover, to the extent that he was acting as an investigator or director of the investigation, he was not doing so in a way that precluded him from being an expert witness in the case. Evans’ evidence was provided without him being given access to the other circumstantial material, so it was uninfluenced by matters outside his expertise and knowledge. Also, his opinions were independently corroborated by other expert witnesses.
As for being the subject of previous adverse judicial comment, Evans pointed out that the document in question was not in fact an expert witness report for Court, but a letter to solicitors in a care case. It had been used by them without his knowledge or consent in applying for permission to appeal. The criticism was put to him; he had not been aware of it before; he explained his understanding of the context; the matter was left for the jury to consider. The Court found nothing wrong with that approach.
Air Embolus in Neonates
Letby sought to admit fresh evidence in the form of two reports from a neonatologist, Shoo Lee, to address the defense assertion that the prosecution experts were wrong to diagnose air embolus on the basis of a research paper. The Court held that ““although their direct clinical experience of air embolus in neonates was inevitably very limited, each of the prosecution’s expert witnesses was well qualified in their respective fields to give the evidence which they gave.”
Defense did not call any expert witness evidence at trial
It was open to the defense to call expert evidence of their own. They did instruct a number of experts and serve their reports on the prosecution, but they did not call any expert witness evidence at trial.
In the trial, the result was that the prosecution expert witnesses were challenged strongly by the defense; but the points made in the challenge could only become evidence in the case if, either the defense called their own witnesses who could then provide that evidence, or the prosecution witnesses accepted the points made in the challenge.
Held
The Court of Appeal admitted Dewi Evans’ testimony and rejected Letby’s application for leave to appeal against her convictions.
Key Takeaway:
Evans was familiar with the courts’ approach and ready to deal with the inevitable challenges of the criminal justice system.
The issue of admissibility (whether or not evidence is put before the jury) is a question of law which is dealt with by the judge. If they rule that the evidence is admissible, it is then considered by the jury. The ruling to admit the evidence can be challenged on appeal.
The issue of the weight to give to any evidence is a matter entirely for the jury. Counsel can seek to persuade them to take one view or another of the evidence. The judge must leave it up to the jury. What weight the jury has in fact given to each piece of evidence might be inferred from the verdict that they reach.
