The Archbishop of York has warned that Britain was in danger of "coming close to a police state" in the wake of the arrest of suspected terrorists in Birmingham.
Dr John Sentamu, who fled Uganda in the 1970s, criticised 90-day detention, likening it with his home country under the tyrannical rule of Idi Amin.
"If you detain people, you must have good enough reason for detaining them and have a chance for there being a successful prosecution," he said.
He continued: "The Home Secretary has not produced the evidence that shows that in 90 days you're capable of getting somebody prosecuted.
"Why does he want these days, so the police do what? Gather more evidence? To me that becomes, if you're not very careful, very close to a police state in which they pick you up and then they say later on we'll find evidence against you. That's what happened in Uganda with Idi Amin."
He spoke out in an interview with ITV News as West Midlands Police continued to question nine people arrested in Birmingham over an alleged plot to kidnap and murder a Muslim soldier.
The Archbishop also urged people coming to live in the UK to adopt and "cherish" British values.
The second most senior cleric in the Church of England said: "If you are in Britain and you're British, you should really cherish the traditions that are here.
"In a (democratic) country like this to then say: I am going to kidnap somebody, I'm going to kill somebody, I will blow people up - for whatever ideology that is about - it isn't good citizenship.
"If you don't actually subscribe to the things that make Britain, you're going to be in trouble."
