This FOI has some information;
https://www.whatdotheyknow.com/request/number_of_mscarriages_of_justice
"Out of “78 individuals whose convictions were quashed by the Court of Appeal between 1st April 2006 and 31st March 2009” the causes were;
- New Expert (non- medical) evidence: 7 (covering a range if issues from DNA to false confessions and psychiatric reports).
- Discredited expert witness: 3 (this is a single case with three co-defendants).
- New medical evidence: 3.
- Unreliable witness / miscellaneous new witness: 11 (basically where new information about a witness, often but not always the complainant, or new witness testimony has been obtained to undermine the safety of the conviction.)
- Non-disclosure of material to the defence -13 (the accidental or deliberate non-disclosure, by prosecuting or investigating authority, of material which might have assisted the defence or undermined the prosecution and which the disclosure rules say the defence should have had access to).
- Misconduct by police or other authorities (such as HM Customs and Excise) – 15 (15 individuals involved in six actual cases)
- Judicial / process failure: 10 (issues such as errors in summing up, jury directions, not making alternative counts available for the jury to consider – this includes two cases involving a ruling by the House of Lords to clarify a point of law about causation in manslaughter conviction)
- One case was referred on grounds of defence incompetence.
- One was a magistrates’ court case related to planning law
I think that only case was the defence and the rest were the police, prosecutor and courts says it all.