One of the murderers of Lee Rigby has been described as Britain’s most dangerous prisoner because he is brainwashing fellow inmates.

Islamic extremist Michael Adebolajo, 31, has been called ‘violent, unpredictable and a major danger to other prisoners’.

He was jailed for life without the possibility of parole for the murder of Fusilier Lee Rigby on May 22, 2013.

View photos Lee Rigby was murdered in May 2013 (Picture: PA) More

Adebolajo and his accomplice Michael Adebowale ran Mr Rigby over in a car before attacking him with a meat cleaver and knives in Woolwich, southeast London. Adebowale was jailed for 45 years.

Adebolajo, born in Lambeth, south London, was moved from Belmarsh Prison in London to HMP Frankland in County Durham, another Category A prison, in 2014.

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A prison official told The Mirror that Adebolajo has managed to radicalise other inmates.

The newspaper reported that ‘dozens of prisoners’ have been recruited by Adebojalo.

View photos Lee Rigby’s killers, Michael Adebolajo and Michael Adebowale (Picture: PA) More

‘Adebolajo spends most of his waking hours preaching his distorted form of Islam to anyone who will listen,’ the source said.

‘He sees every inmate as a potential Islamic State soldier whether they are Muslims or not.

‘He has a big personality and is very charismatic and some of the more vulnerable prisoners will fall under his spell. He is a very dangerous individual.’

The Mirror reported that the official said Adebolajo sees his role as recruiting as many Jihadis as possible.

But the source claimed the prison cannot constantly monitor his activities.

View photos Lee Rigby was off duty when he was attacked (Picture: Rex) More

‘If he is suspected of trying to radicalise other inmates we step in and move him,’ the official said.

‘But even in prison Adebolajo cannot be watched all the time. We don’t have the staff or the resources.’

HMP Frankland also holds Yorkshire Ripper Peter Sutcliffe, child murderer Ian Huntley and Levi Bellfield, the murderer of Milly Dowler.

The Professional Trades Union for Prison, Correctional & Secure Psychiatric Workers (POA) said Adebolajo cannot be watched constantly because of a lack of resources.

‘There aren’t enough staff to monitor what he does – and it’s not just him,’ a spokesman said.

He said there are a number of prisoners ‘hell-bent on grooming’ other inmates.

A spokesperson for the Ministry of Justice said: ‘We do not comment on individual prisoners.’