An inquiry has been launched into allegations that several policemen knew young women were being abused at the home of Rosemary and Frederick West and that three officers used the house as a brothel.
A senior officer from a police force not connected to the West case will carry out the investigation, under the supervision of the Police Complaints Authority.
But Douglas French, MP for Gloucester, said last night the inquiry did not go far enough. He called for a public inquiry into the handling of the West case by police and social services and dismissed the PCA investigation as inadequate.
"There needs to be a public inquiry into all aspects of this case, not just into a few narrow areas. If we are to learn from what happened we have got to bring in a wide range of expert views," he said. "I have never been happy with police investigating police. Independent people should be used to investigate the complaint."
Yesterday's development follows allegations from a 33-year-old witness, known only as Sharon X for legal reasons, who claims she was at 25 Cromwell Street when police officers visited for sex. She also alleges that they used the home as an illegal drinking club. She said this happened over the same period that the Wests were torturing and killing women and girls at the house.
The mother of two stayed at the West household after running away from Jordans Brook, a nearby children's home. She has named three officers who she claims used the Wests home as a brothel and a drinking club. The names of a further three officers, who allegedly knew that sex was available at the house, have also been forwarded to the PCA.
Sharon X told the Daily Express that on one occasion she was tied to a chair after having been assaulted. "The next thing I was aware of was a man in a beige raincoat coming in. He had a policeman's uniform on underneath. The man freed me and told me to get out quickly. There was a lot of commotion."
She reportedly added: "I used to see this policeman a lot at the house. I remember his serial number, and his shirt, his uniform he always wore under that coat. I remember him and another policeman would be at the house."
During the murder investigation she was questioned several times, but was told that no one matched the name and serial number she provided. She was not called to give evidence in the trial of Rosemary West, who was convicted last week of 10 murders.
Sharon X wrote to the PCA, an independent organisation, saying that the original allegations about the police officers had not been investigated properly. The authority forwarded the letter to Gloucestershire police. Tony Butler, the Chief Constable, voluntarily referred the case and will select an officer from an outside force to carry out the inquiry.
A statement from Gloucestershire police said: "In view of the nature of these complaints the force will be seeking to appoint a senior officer from another force area to conduct the inquiry."
However, the use of a police inquiry overseen by the PCA was criticised yesterday. A spokeswoman for Liberty, the civil rights organisation, said: "The PCA is not wholly independent or accountable - police officers are still investigating the police."
Chris Mullin, the Labour MP and campaigner against miscarriages of justice, added: "The PCA should be given the powers to do its job properly - this should include ensuring that inquiries are conducted by people who are not police officers."
It also emerged yesterday that Gloucestershire social services used private detectives to check up on Frederick and Rosemary West while their children were in care.
The detectives were used in 1993 by the council, which was concerned that the couple were breaching a court order preventing unsupervised contact with the children.