Former Cabinet minister Robin Cook says he is "deeply troubled" by an increase in raids to prevent terrorism.
Robin Cook reiterated his criticism of the Iraq war
Mr Cook said "raids under the Anti-Terrorism Act...are now running, staggeringly, at 10 times the level of three years ago".
He said such raids risked "alienating" the very people Britain needed for a multi-cultural society.
He was speaking at the Edinburgh Book Festival on Monday where he made the annual Donald Dewar speech.
"I'm deeply troubled by the increase in raids," he told the packed audience.
"There were 30,000 raids under the Prevention of Terrorism Act last year from which less than 100 individuals were charged with offences relating to terrorism."
He added: "There's a real risk that if we continue with that we will end up alienating the very people we need for a successful multicultural society and a successful appeal to people around the world of a different culture."
Mr Cook, who quit the Cabinet over his opposition to the Iraq war, warned prime minister Tony Blair that such a military campaign could not be repeated.
"Iraq is unique, it's a one-off." he said.
"It's exhausted Tony Blair's capacity to take the nation to war against any substantial resistance."
He added: "If he hopes to bring back to the Labour Party all those millions who opposed the war or those who supported it on the basis he sold it to them he's got to make it plain that he's learned the lessons from the past two years and that is going to be different in the future."