Five men who were due to go on trial accused of being a part of a paedophile gang have had all charges against them dropped following serious concerns about the evidence given by the accuser.

Retired GP Stephen Glascoe, 67, and 61-year-old former social worker Patrick Graham, 61, were accused along with three other men of raping a woman in Cardiff in the late 1980s and early 1990s.

The alleged victim came forward to claim she was abused multiple times between the ages of three and 15, as well as being given a forced abortion and being made to torture other children.

The woman, who cannot be named for legal reason, recalled the alleged abuse while undergoing controversial regression therapy.

However, two weeks before the trial was due to take place, the case has been dropped after doubts were raised about the woman's claims and her relationship with the investigating officers.

Among one of the key issues was her account of the abortion which Glascoe was accused of performing in his attic, which a consultant gynaecologist described as "physically impossible" and appeared to be based on scenes from the film Vera Drake and the BBC TV show Call the Midwife, reports The Times.

It also emerged that police knew the woman after she made a false rape allegation as a teenager and that she also claimed one of the men due to stand trial had sent her an Amazon package containing twisted wires similar to ones which were tied to her wrists when she was abused. She later admitted she sent the item to herself.

Christopher Clee, QC, defending Dr Glascoe, said that the woman had "throughout manipulated the proceedings, disclosing incidents of alleged abuse as and when it suits her purposes; these allegations emerging through counselling sessions which in themselves are of dubious standing".

He added: "She has found a powerful ally in the police, who have acted upon her allegations without question, ignoring obvious lines of inquiry and seeking to undermine potential evidence that contradicts her allegations."

Judge Thomas Crowther at Newport Crown Court ordered all men to be found not guilty and raised questions about the conduct of detective constable Beverly Norman after it was revealed the pair had exchanged 1,000 text messages, 530 emails and 118 telephone calls during the 18-month investigation.

The men are now calling for a national review into how police handle rape allegations.

Glascoe told the Times: "It was not long ago that women who were victims of rape were denied justice because the police did not believe them. Then after Jimmy Savile everything changed, and the pendulum has swung too far the other way.

"Allegations must be treated seriously but not unquestionably and believed from the outset. Rape and serious sexual assaults are common and false allegations are rare, but I know what happened to me is not unique."

A South Wales police spokesperson said: "Throughout any investigation we regularly communicate with the victim in order to offer them support and keep them updated on progress.

"This particular case involved a vulnerable woman who required additional support, not only throughout the investigation but in the lead-up to the court case.

"She lived outside Wales, which meant that officers had to rely on electronic means of communication, such as text messages and email."