Frederick West claimed that he and his wife, Rosemary, had killed 20 more victims than those found at 25 Cromwell Street, bringing the total to more than 30, Winchester Crown Court was told yesterday.
The couple had been involved in the killings with several other men and some of the bodies had been buried at a farm, West told Janet Leach, an observer who was appointed to sit in on his police interviews.
Mrs Leach, 39, was resuming her evidence at the murder trial of Mrs West, six days after collapsing at the court and being taken to a Winchester hospital, where she had been receiving treatment ever since.
Mrs Leach claimed West told her that he and others were involved in killings, other than those at his Cromwell Street home, and the bodies were buried at an unnamed farm.
Looking pale and drawn, Mrs Leach, 39, who suffered a stroke last year, was pushed into the witness box in a wheelchair and was accompanied by Dr Christopher Gordon from the hospital throughout her evidence.
The trial of Mrs West, 41, who denies murdering 10 girls and young women whose remains were found at the Wests' house, 25 Cromwell Street, Gloucester, and at their previous home in the city, entered its seventh week yesterday.
Last week Mrs Leach told the court that she was appointed an "appropriate adult" to sit in as an impartial observer at police interviews with West after his arrest last year.
She said that she established a rapport with West and that while detectives were not present he told her that he had made a pact with his wife by which he would take sole responsibility for the killings if they were caught.
Mrs Leach wept and paused frequently to take sips of water yesterday as she continued her account of her conversations with him.
West, who was charged with 12 murders, was found dead in his prison cell last New Year's Day.
Asked by Brian Leveson QC, prosecuting, how many more bodies West was talking about, Mrs Leach replied: "Another 20."
He did not tell her precisely where they were buried and said that Mrs West, another person and some coloured men had been involved in the killings.
Mrs Leach said that one of the victims missing was cafe waitress Mary Bastholm, 15, who vanished in January 1968.
She learnt that Mary was dead and buried at an undisclosed farm. West, she said, told her that he picked Mary up at a bus stop. The jury has already heard that some of the alleged Cromwell Street victims were picked up at bus stops.
Mrs Leach admitted lying in her evidence last weekover whether she had spoken to the press. She agreed that she had been paid a pounds 7,500 option for a book deal which could eventually be worth pounds 100,000.
Report, page 7