Serial rapist and killer John Duffy told the Old Bailey this week how he feared his alleged partner in crime was continuing with their attacks while he was serving life in prison.

Duffy, 42, dubbed the 'railway rapist', is testifying against former schoolfriend David Mulcahy, who is charged with three murders and 12 counts of rape and conspiracy to rape. He denies all charges.

Mulcahy, 41, of Beaumont Walk, Hampstead, was alleged to have committed these crimes except the murder of Potters Bar newlywed Anne Lock alongside Duffy who is now serving a life sentence in prison for two murders and six rapes.

Duffy was acquitted of Mrs Lock's murder in 1988 when he was jailed for life for two murders and six rapes but has since admitted raping her.

The court heard a report on Duffy by a psychologist. It said: "He has mixed feelings about David and fears he might have reoffended again.

He thinks he should pay for what he has done."

Duffy then told the jury: "I wanted to get it off my chest completely but giving evidence against another person is like putting my life on the line with the other prisoners."

Earlier Duffy told the court that he and Mulcahy had planned to gang rape women in their homes as teenagers.

"We would plan where to go, how to get there and exactly what we were going to do.

"You know like where we were going, what we would do and, of course, who was going to rape first."

During cross-examination by George Carter-Stephenson, Duffy also admitted planning burglaries with the intent of raping any lone females he may have found.