False confessions responsible for many flawed convictions: Heather Mills on the reasons why some innocent suspects admit crimes

SURPRISING though it may seem, a false confession is very common and a frequent cause of wrongful imprisonment.

It has been responsible for some of the country's most deplorable miscarriages of justice. Stefan Kiszko, who confessed to murdering an 11-year-old girl, was cleared after 16 years in prison when scientific tests proved incontrovertibly that he could not have been the attacker.

Judith Ward had been confessing to all sorts of IRA activity for a number of years before she was finally arrested after claiming responsibility for the M62 coach bombing. She was cleared last year, after it was proved her 'outpourings' were the product of mental illness.

The Birmingham Six, the Tottenham Three and a series of other cases have all involved retracted false confessions.

Psychiatrists, psychologists and the legal fraternity are now well aware of the dangers and unreliability of uncorroborated confession evidence. Research recently undertaken for the Royal Commission on Criminal Justice recommends that confessions, unsupported by any other evidence, should no longer be admissible as evidence. The British Psychological Society has urged that judges, prosecutors and police should be taught about the fallibility of confession evidence to try to avoid miscarriages of justice.

Dr James MacKeith, a consultant psychiatrist, and Dr Gisli Gudjonsson, a forensic psychologist, are at the forefront of research on false confessions. They have come across hundreds of people who have confessed to crimes they did not commit. They found that most fall into three main groups.

The first are voluntary confessors - fantasists seeking notoriety, the mentally ill or disordered and depressives prompted by a general sense of guilt or desire to be punished for a previous transgression. It is not uncommon for disturbed people to walk into a police station and confess to a crime they have read about in the newspapers.

The second are those with psychological weaknesses that make them unable to resist interrogative pressure. The 'coerced-compliant' confession is usually the result of forceful or persistent questioning, where confessors are so desperate to escape the stress of interrogation that they will say virtually anything, without thinking through the consequences.

The 'coerced-internalised' false confession, by contrast, involves an innocent suspect being persuaded during interrogation that he or she actually committed the crime.

Both Dr Gudjonsson and Dr MacKeith examined Carole Richardson, one of the Guildford Four, before their 1989 appeal. They found that she had strong tendencies to avoid conflict and confrontation, and was very vulnerable to interrogative pressure. On top of that she was abusing drugs at the time making her more vulnerable. Initially, Ms Richardson was clear in her own mind that she had nothing to do with the bombings, but confessed so that the police would leave her alone.