Nick Hardwick, who will retire as Chief Inspector of Prisons in the New Year, stressed that officers should not be deterred from tackling gang-related activity in jails.
"There are undoubtedly a small number of very dangerous men motivated by a religion or ideology who are trying to recruit other people so they will go on to commit offences linked to that ideology or religion," he told The Times.
"You do have Muslim gangs but the point about it is, it is a gang. That is more important than it is Muslim. There might be pressure to join up, but how real that conversion is, is the big question," Hardwick said.
UK prison chiefs fear the bigger problem than radicalisation may be the influence of Muslim gangs and their attempt to use their faith as a cover for violence and intimidation, the report said.
Also Read
According to an analysis of prisons data, there are 12,600 Muslim prisoners in jails in England and Wales. In some top security prisons they make up a large proportion of the overall population.
Among them are prisoners with extremist views who have threatened violence towards non-Muslims. Others are suspected of pressurising non-Muslims to convert to Islam.