The Chief Inspector of Prisons Anne Owers also expressed fears about radical Muslim gangs trying to force other inmates to convert to the religion.

Ms Owers said the situation urgently needed addressing at the high-security jail, near March, where almost a third of inmates are Muslims.

She said: "There was a perception among officers that some Muslim prisoners operated as a gang and put pressures on non-Muslim prisoners to convert, and on other Muslim prisoners to conform to a strict and extreme interpretation of Islamic practice."

Ms Owers found officers at Whitemoor were reluctant to tackle "inappropriate behaviour" and was told Muslim prisoners were able to "police themselves".

She said officers also tended to treat Muslim inmates as extremists and potential security risks, despite the fact that only eight had been convicted of terror offences.

She added: "The Prison Service as a whole needs to equip staff better to deal with the growing number of Muslim prisoners. The inspection and others have charted a growing disaffection and distance between those prisoners and the prison system, a gap which urgently needs to be bridged."