Sir David says he has been impressed by private jails he had visited where inmates are formally addressed by the titles Mr or Ms.

Speaking on BBC Radio 4's Today programme, Sir David said the Prison Service was concerned about "humanity" in its treatment of prisoners.

Sir David Ramsbotham: "Nothing more human than calling you by your name"

"There is nothing more human than calling you by your name," the chief inspector said. "We have noticed it in private sector prisons in the last three years.

"There is no doubt that the control that seems to come with it, which is commented on by prisoners and staff, suggests there is something to it."

Bev Lord, from the Prison Officers Association, gave a cautious welcome to the suggestion, pointing out that in jails with a rapid turnover of prisoners it was impossible for staff to know the names of even half the inmates.

She said that in longer term jails, first names were sometimes used between staff and inmates.