Sir Peter was commenting on a television investigation which revealed prisoners in some jails were regularly being asked to squat or bend over during strip searches.
Such practices are only permitted when a prisoner is "under suspicion" but an investigation by BBC1's Nine O'Clock News found that the practice became routine in many prisons as part of a security crackdown.
The Director General of the Prison Service, Richard Tilt, last night warned prison governors not to abuse the guidelines on strip-searching inmates
"I am reminding governors that squatting and bending must only be done where there is reasonable suspicion ... and if you [the BBC] have evidence that it is widespread, of course I will investigate," he said.
His warning coincided with the Prison Service's decision to reduce the prison category of Roisin McAliskey, the pregnant 25-year-old being held on remand in connection with the IRA mortar attack on a British army barracks at Osnabruck, Germany, last year.
Ms McAliskey, daughter of the former nationalist MP Bernadette Devlin, was previously a Category A high-risk prisoner in Holloway Prison, north London, which meant she was strip-searched before and after prison visits.
Now, as a Category A standard-risk prisoner she will be strip-searched less often and will be allowed access to a dress-making craft shop in the prison.
Recent reports that Ms McAliskey was told she must give birth in handcuffs and will not be allowed to care for her baby in prison were strongly disputed by the Prison Service who said it made clear in January 1996 that women would not be handcuffed during childbirth.
Ms McAliskey is due to give birth in May.
A decision is expected next week on whether her new prisoner status will allow her to be accommodated with her baby when it is born.Reuse content