'I was recruited by extreme Islamists in Woodhill jail,' claims former Milton Keynes prisoner

The man, who has not been named, claimed Woodhill had its own own self-appointed 'emir', who oversaw the makeshift court and encouraged young Muslim inmates to become radicalised.

He told the Times newspaper he took part in the 'trial' of two prisoners who had allegedly disrespected Islam by drinking alcohol.

The men were found guilty and both received beatings as their punishment.

The informant alleged the group had access to recordings of senior al-Qaeda member Anwar al-Awlaki. They also circulated banned books to inmates, he said.

He claims he was sent messages by the Woodhill group after leaving prison, offering him a passage to Syria.

The subject of radicalisation in Britain’s prisons has come under scrutiny since the recent attack at London Bridge last month, when Usman Khan, a Category A terrorist prisoner freed on parole, killed two people before being gunned down by police.

Richard Walton, former head of Scotland Yard’s Counter Terrorism Command, claims reforms to tackle the problem have ground to a halt.

He said: “It is unsurprising radicalisation continues to be a significant challenge, owing to the success in recent years of convicting high numbers of Islamist terrorists for plotting attacks.”