However, when the same warder looked in his cell through an observation window just over an hour later, she saw him hanging.

BBC: Aylesbury Young Offender Billy Spiller 'like a tornado'

But for Mr Steinberg's tough prison-warder colleagues it is a distraction, or worse, from the job of keeping their charges under control.

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When a prison warder checked on him at 13:00 GMT, Spiller said he was feeling better, after being allowed to make the phone call.

BBC: Aylesbury Young Offender Billy Spiller 'like a tornado'

For these reasons, former prison governor and warder Roger Outram is doubtful that more than a handful of British inmates would actually bother to participate.

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"We have 25 dead from yesterday's attacks in Ganye which included a chief prison warder, a policeman and a prominent politician, " Adamawa state police chief Mohammed Ibrahim was quoted by AFP news agency as saying.

BBC: Nigerian town of Ganye hit by deadly attacks