Police Chief wants extremists to be locked in internment camps

From earlier this year - http://www.dailymail.co.uk/news/article-4548870/Ex-Met-chief-calls-internment-camps-3-000-extremists.html

'Thousands of radical extremists must be locked up in new internment camps to protect Britain from the unprecedented terror threat it faces, a Muslim former police chief declares today.

Writing exclusively for The Mail on Sunday, Tarique Ghaffur warns there are too many extremists on the streets for police and MI5 officers to monitor.Mr Ghaffur, an Assistant Commissioner at Scotland Yard when the 7/7 bombings took place, proposes that special centres be set up to detain as many as 3,000 extremists, where they can be kept from launching attacks. They would also be made to go through a de-radicalisation programme.'

Only 3,000 extremists? Would a deradicalisation programme work?