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Prof Peter Hindmarsh, King of Insulin

Updated: Oct 4

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The doctor is being investigated by the GMC

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Update on reporting restrictions: I have not sought legal advice about what the reimposition of reporting restrictions means for what I can write in relation to Lucy's case but I have spoken to someone who knows about these things. The test is whether a published report poses a "substantial risk of serious prejudice." The trial to which the reporting restrictions pertain is a year or so away (it hasn't even started!) Also, this article is about Peter Hindmarsh and insulin, which had nothing to do with Child K (the case being retried).

Prof Peter Hindmarsh is a paediatric endocrinologist at UCLH.

Prof Peter Hindmarsh testified at Lucy's trial in November last year that, in relation to Child F's blood test result, "the insulin reading should be in proportion to the insulin C-Peptide reading" and the fact that it wasn't (insulin to c-peptide ratio was very high) meant exogenous insulin had been administered. He said this despite the guidance from Royal Liverpool University Hospital (RLUH) that conducted the test ( stating, "Please note that the insulin assay performed at RLUH is not suitable for the investigation of factitious hypoglycaemia. If exogenous insulin administration is suspected as the cause of hypoglycaemia, please inform the laboratory so that the sample can be referred externally for analysis." (red in document not mine). The reason is that the RLUH test picks up non-poisonous insulin analogues such as proinsulin and insulin antibodies, not just insulin. The further test, that it seems was not conducted, is more sensitive and would have measured the amount of insulin and thus the correct insulin to c-peptide ratio.

Prof Peter Hindmarsh testified at Lucy's trial in February this year in relation to Child L's blood test result. According to , Hindmarsh, said "the results of a blood sample taken some time on the afternoon of April 9 meant he was “quite certain” that non-natural insulin was present in his system." This despite RLUH's guidance ( clearly stating the assay should not be used to test for exogenous insulin. Other expert testimony (, copied below) was provided by clinical biochemist Dr Anna Milan (Dr Gwen Wark, head of the Guildford lab that performs more detailed analysis, also testified). It seems that Milan as well as Hindmarsh incorrectly testified that the RLUH's test result showing a high insulin to c-peptide ratio (it didn't, it showed a high insulin plus proinsulin plus insulin antibodies to c-peptide ratio) meant that exogenous insulin had been administered. Milan had testified in November in the relation to Child F ( , copied below) that "Guildford has a specialist, separate laboratory for such analysis in insulin, although the advice given to send the sample is not usually taken up by hospitals. Dr Milan said that advice would be there as an option for the Countess of Chester Hospital to take up. Dr Milan (co-author of , Forensic aspects of insulin) said she was 'very confident' in the accuracy of the blood test analysis produced for Child F's sample." It is certainly not clear from the brief report of Wark's testimony that the two blood samples were sent to Guildford.

Prof Peter Hindmarsh is, as of 21 April this year, the subject of a General Medical Council investigation (big shout out to the member of this blog that put me onto it) that as of today is still ongoing (, details copied below).


1. You'd have thought that by April 2016 (collapse of Child L), eight months after senior consultant Dr Brearey (said he had) first noticed an association of events with Lucy, the doctors would have been keen to send the blood sample for additional analysis. Even Child F's collapse in August was a couple of months after Brearey's supposed observation and thus should have warranted further analysis.

2. The two insulin cases were the first to be decided upon by the jury (both unanimous 11-0 guilty verdicts). It may have been easier for jurors thereafter to believe Lucy guilty of committing other crimes. In other words, if the insulin cases can get thrown out because Hindmarsh's testimony gets thrown out, that should have ramifications for the other verdicts (legally, it may not, but we here are in the business of influencing public opinion too).

Following publication of my article, one of my blog members posted the below insightful comment:

Interesting comment, Peter, in your conclusion to The King of Insulin -- regarding the ramifications for the other convictions if F and L are overturned.

In the Judge's summing up he said to the jurors, [my parenthesis and bold highlights]:

"If you are satisfied so that you are sure in the case of any baby [eg F and L] that they were deliberately harmed by the defendant then you are entitled to consider how likely it is that other babies in the case who suffered unexpected collapses did so as a result of some unexplained or natural cause rather than as a consequence of some deliberate harmful act by someone.

“If you conclude that this is unlikely then you could, if you think it right, treat the evidence of that event and any others, if any, which you find were a consequence of a deliberate harmful act, as supporting evidence in the cases of other babies and that the defendant was the person responsible."

The Judge wouldn't use the word 'entitled' lightly, it seems to be a point of law he is referring to. As you say, the verdicts in F and L were the first ones the jury decided on.

It does indeed then look like they used those decisions for F and L as justification against Lucy for all the remaining ones she was convicted upon. However we'll never know, what goes on in the jury room remains in the jury room.

But given the judge's remarks it looks very like the right path to pursue to bring down this whole house of cards --starting just as soon as word gets out how shoddy the police and scientific investigation has really been regarding the inappropriate insulin investigation.

I then noted the similarity to Colin Norris ("insulin killer nurse") and the referral of his case by the CCRC (nearly two years ago!) to the CoA:

Somewhat similar to CCRC's referral of Colin Norris' case to CoA. From "As regards the murder of Mrs Hall, the CCRC considers that this conviction depends upon support from the other 4 cases and the prosecution’s assertion that no-one other than Mr Norris could have been responsible. In light of the new expert evidence, the CCRC is satisfied that this assertion is now less secure and that, as a result, there is a real possibility that the Court of Appeal will quash this conviction too." It is of course also shocking that this was written nearly two years ago and still nothing from CoA.

Testimonies of Dr Anna Milan and Dr Gwen Wark:

Dr Anna Milan (child F)

The court is hearing from Anna Milan, a clinical biochemist, how insulin and insulin c-peptide tests were taken for analysis. Child F's blood sample, which was dated August 5, 2015, was taken at 5.56pm. The court is shown a screenshot of Child F's blood sample results. Child F is referred to as 'twin 2' - Child E, the other twin boy, had died at the Countess of Chester Hospital on August 4. Dr Milan says Child F's insulin c-peptide level reading of 'less than 169' means it was not accurately detectable by the system. The insulin reading of '4,657' is recorded. A call log information is made noting the logged telephone call made by the biochemist to the Countess of Chester Hospital, with a comment made - 'low C-Peptide to insulin'. The note adds '?Exogenous' - ie query whether it was insulin administered. The note added 'Suggest send sample to Guildford for exogenous insulin.' The court hears Guildford has a specialist, separate laboratory for such analysis in insulin, although the advice given to send the sample is not usually taken up by hospitals. Dr Milan said that advice would be there as an option for the Countess of Chester Hospital to take up. Dr Milan said she was 'very confident' in the accuracy of the blood test analysis produced for Child F's sample.

Cross Examination

Ben Myers, for Letby's defence, asks about the risk of the sample deteriorating if it is not frozen. Dr Milan said the sample arrived frozen. If it wasn't frozen, it would be accepted in 12-24 hours. She said the laboratory knew it arrived within 24 hours, and adds Chester has its own system in place to store the blood sample before transport. Mr Myers said the Child F blood sample would have been stored for seven days [in Liverpool], then disposed of. Dr Milan agrees. On a query from the judge, Mr Justice James Goss, Dr Milan explains how the blood sample is frozen and kept frozen for transport. She said the sample would not have been taken out of the freezer in Chester until it was ready to be transported.

Dr Anna Milan (child L)

From Dan O’Donohue Twitter (20/02/2023)

Anna Milan, a clinical biochemist, is giving evidence about a blood sample analysis that was carried out for Child L. The analysis was to test for insulin. Court is being shown blood analysis results for Child L (they were collected on 9 April 2016). Ms Milan said the 'only way you get a pattern like that is if insulin has been given to a patient'

Cross Examination

Ben Myers KC, defending, is now questing Dr Milan on the process for analysing blood - from ward to lab. She says 'ideally' blood will be taken and cooled within 30minutes to preserve it. Mr Myers asks if blood is left for hours, will it cause issues - 'it can do yes'. Mr Myers asks if a sample hasn't been handled correctly, will it affect the relatability of the findings - and specifically in this case. Dr Milan says it can effect findings, but it 'wouldn't create insulin in this sample' Dr Milan repeats, that the only explanation for the readings in this sample is external administration

Dr Gwen Wark (child L)

From Dan O’Donohue Twitter (20/02/2023)

Dr Gwen Wark is now in the witness box. She is the director of the Guildford RSCH Peptide Hormone Laboratory. Her evidence again focuses on the blood analysis of Child L. Dr Wark's evidence relates to the veracity of the blood test results. She confirms Child L's reports met all required standards

From Prof Peter Hindmarsh's GMC entry (

Hearings (since 20 October 2005): 21 Apr 2023 Interim Orders Tribunal

Conditions on the doctor's registration (From 21 Apr 2023):

1. He must personally ensure that the GMC is notified of the following information within seven calendar days of the date these conditions become effective: a of the details of his current post, including: i his job title ii his job location iii his responsible officer (or their nominated deputy) b the contact details for his employer and any contracting body, including his direct line manager c of any organisation where he has practising privileges and/or admitting rights d of any training programmes he is in e of the contact details of any locum agency or out-of-hours service he is registered with.

Glossary V16

2. He must personally ensure the GMC is notified: a of any post he accepts, before starting it b that all relevant people have been notified of his conditions, in accordance with condition 7 c if any formal disciplinary proceedings against him are started by his employer and/or contracting body, within seven calendar days of being formally notified of such proceedings d if any of his posts, practising privileges or admitting rights have been suspended or terminated by his employer before the agreed date within seven calendar days of being notified of the termination e if he applies for a post outside the UK.

Glossary V16

3. He must allow the GMC to exchange information with his employer and/or any contracting body for which he provides medical services.

Glossary V16

4. When undertaking patient facing clinical work, he must only do so at University College of London Hospitals NHS Trust.

Glossary V16

5. He must notify any instructing organisation when acting or accepting instructions as an expert witness as to this and any ongoing GMC investigation.

Glossary V16

6. a He must be directly supervised in all of his posts by a clinical supervisor, as defined in the Glossary for undertakings and conditions. His clinical supervisor must be appointed by his responsible officer (or their nominated deputy). b He must not work until: i his responsible officer (or their nominated deputy) has appointed his clinical supervisor and approved his supervision arrangements ii he has personally ensured that the GMC has been notified of these arrangements. c He must provide a report from his clinical supervisor in advance of or at his next IOT review hearing.

Glossary V16

7. He must personally ensure that the following persons are notified of the conditions listed at 1 to 6: a his responsible officer (or their nominated deputy) b the responsible officer of the following organisations i his place(s) of work and any prospective place of work (at the time of application) ii all his contracting bodies and any prospective contracting body (prior to entering a contract) iii any organisation where he has, or has applied for, practising privileges and/or admitting rights (at the time of application) iv any locum agency or out-of-hours service he is registered with v if any organisation listed at (i to iv) does not have a responsible officer, he must notify the person with responsibility for overall clinical governance within the organisation. If he is unable to identify this person, he must contact the GMC for advice before working for that organisation. c the approval lead of his regional Section 12 approval tribunal (if applicable) - or Scottish equivalent d his immediate line manager and senior clinician (where there is one) at his place of work, at least 24 hours before starting work (for current and new posts, including locum posts).

Glossary V16

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The views expressed in this communication are those of Peter Elston at the time of writing and are subject to change without notice. They do not constitute investment advice and whilst all reasonable efforts have been used to ensure the accuracy of the information contained in this communication, the reliability, completeness or accuracy of the content cannot be guaranteed. This communication provides information for professional use only and should not be relied upon by retail investors as the sole basis for investment.

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