Clark's case was referred back to the Court of Appeal by the Criminal Cases Review Commission, and her convictions were overturned at her second appeal in January 2003. She was released from prison having served more than three years of her sentence.

Meadow's calculation was based on the assumption that two SIDS deaths in the same family are independent. The RSS argued that "there are very strong reasons for supposing that the assumption is false. There may well be unknown genetic or environmental factors that predispose families to SIDS, so that a second case within the family becomes much more likely than would be a case in another, apparently similar, family."

The ruling was also subject to a statistical error known as the "prosecutor's fallacy". Many press reports of the trial reported that the "1 in 73 million" figure was the probability that Clark was innocent. However, even if the "1 in 73 million" figure were valid, this should not have been interpreted as the probability of Clark's innocence. In order to calculate the probability of Clark's innocence, the jury needed to weigh up the relative likelihood of the two competing explanations for the children's deaths. In other words, murder was not the only alternative explanation for the deaths in the way that one might have inferred from asserted probability of double SIDS. Although double SIDS is very rare, double infant murder is likely to be rarer still, so the probability of Clark's innocence was quite high. Hill calculated the odds ratio for double SIDS to double homicide at between 4.5:1 and 9:1, that is double SIDS is twice as likely as double murder. Then current GMC professional conduct guidance did not support his 'professional etiquette' reason. He was reinstated in 2006 after he appealed and the court ruled (2 to 1) that his actions in court had amounted to misconduct though not serious enough to warrant him being struck off. The senior judge on the panel, Master of the Rolls Sir Anthony Clarke, dissented from the view of his two colleagues. In his opinion Meadow's actions had amounted to serious professional misconduct.

In June 2005, Alan Williams, the Home Office pathologist who conducted the postmortem examinations on both the Clark babies, was banned from Home Office pathology work and coroners' cases for three years after the General Medical Council found him guilty of "serious professional misconduct" in the Clark case. At the same time he had chosen to withhold evidence of infection as a possible cause of the death of the second baby, he changed his original opinion regarding the first baby from death caused by lower respiratory infection to unnatural death by smothering. He failed to give any good reason for this change in opinion and his competence was called into question. His conduct was severely criticised by other experts giving evidence and opinion to the court and in the judicial summing up of the successful second appeal. He was given the opportunity to address the court to explain his decision to withhold the laboratory results. He declined to do so. Earlier that year he had successfully appealed against the decision to ban him from performing Home Office postmortem examinations; the ban was replaced by an 18-month suspension which by then had passed.

Death

The nature of Clark's wrongful conviction as a child-killer, and her background as a solicitor and daughter of a police officer, made her a target for other prisoners. According to her family, Clark was unable to recover from the effects of her conviction and imprisonment. After her release, her husband said she would "never be well again". but an inquest ruled that she had died of acute alcohol intoxication, though the coroner stressed that there was no evidence that she had intended to commit suicide.

  • David Southall
  • Lucia de Berk
  • Kathleen Folbigg
  • Patricia Stallings
  • Betty Tyson
  • Lucy Letby

References

Bibliography

  • Leila Schneps and Coralie Colmez, Math on trial. How numbers get used and abused in the courtroom, Basic Books, 2013. . (First chapter: "Math error number 1: multiplying non-independent probabilities. The case of Sally Clark: motherhood under attack").
  • John Batt, Stolen Innocence: The Sally Clark Story — A Mother's Fight for Justice Elbury Press, 2004. .
  • Ian McEwan, The Children Act.

Further reading

  • Campaign website
  • Peter Donnelly, "How juries are fooled by statistics", TEDGlobal 2005
  • Article explaining the statistical flaws in the original trial with reference to Bayes Theorem
  • Moreton, Cole. "A broken woman who was haunted to an early grave", The Independent, 18 March 2007.
  • Professor R Hill's website containing links to his articles and papers on the Sally Clark case
  • Neven Sesardić, Sudden Infant Death or Murder? A Royal Confusion about Probabilities, British Journal for the Philosophy of Science 58 (2007), 299-329.
  • Sally Clark's website