The convicted jihadist suspected of carrying out Britain's first terror attack behind bars, had a history of radicalising fellow inmates and even held sharia courts in his cell to punish those who broke strict Islamic laws, it has emerged.

Brusthom Ziamani, 24, and a fellow prisoner allegedly attacked a member of staff at HMP Whitemoor with makeshift weapons on Thursday morning, in what police are treated as a terrorist incident.

The pair, who were wearing fake suicide vests and shouting Allahu Akbar, are accused of slashing and stabbing the prison officer in the face before eventually being restrained by his colleagues, five of whom were also injured.

A former inmate, who was in both HMP Whitemoor and HMP Woodhill alongside Ziamani, has told the Telegraph he was notorious for peddling extremism and trying to convert fellow prisoners to radical Islam.

The source, a white British convert, who has since been paroled and has rejected the radical ideology, said: "When I arrived in prison I was quickly met by Ziamani and allowed into his inner circle.

"He once tried to organise a coup against the prison system and attacked a prison officer. He would also hold sharia courts in his prison cell for infractions such as drinking."