Tony Blair has defended proposals to allow UK terror suspects to be placed under house arrest by ministers without their cases going to court.
Tony Blair is in Davos, Switzerland
The prime minister said the measures were needed to fight global terror.
Home Secretary Charles Clarke said the public had to trust him, Mr Blair and the security services to use the "grave" new powers wisely.
The proposals, which also allow curfews or tagging, have been dubbed an "abuse of power" by the Law Society.
'Death and destruction'
Mr Blair told the BBC in Davos, Switzerland, where he is attending a conference, he was aware of concerns over the destruction of traditional rights and freedoms.
"I pay great attention to the civil liberties of the country. But on the other hand, it is also right that there is a new form of global terrorism in our country, in every other European country and most countries around the world.
"They will cause death and destruction on an unlimited scale and they will and are trying to organise such terrorist activity in our own country. I just hope people get this in perspective."
Earlier Mr Clarke told BBC Radio 4's Today programme it was "unhealthy" to have so much power concentrated in the hands of a few people.
He said he wanted to get as much information as possible about the terror threat into the public domain to allow a proper debate.
But he conceded that some information would have to remain secret - and the public would have to trust the authorities to make sensible judgements about its use to justify detentions.
"A lot of the discussion around this revolves around the extent to which I as home secretary or the prime minister or the head of the security services or the commissioner of the Metropolitan Police can be trusted with the assessments that we make... and that's a real issue."
Chairman of the Bar Council, Guy Mansfield QC, told BBC Radio 4's World at One: "There's a real danger ... that what we end up doing is radicalising minorities.
"We saw it in Northern Ireland - you end up with sleepers in the population and we make this country, ironically, a more dangerous and not a safer place."
The plans were prompted by Law Lords ruling the imprisonment of 12 foreign suspects without trial breaches European human rights laws.
The Law Lords labelled the current regime "discriminatory" because it only applied to foreign nationals.
The Home Office said prosecutions were the government's first preference and promised the powers would only be used in "serious" cases, with independent scrutiny from judges.
UK and foreign terror suspects could also face restrictions on their movements or limits on their use of telephones and the internet, under Mr Clarke's plans.
He has ruled out the use of phone tap evidence in court - seen by civil liberties groups as a way of bringing more suspects to trial - because changing technology could render any legislation obsolete.
But he told the Today programme he would "look at it again" in due course.
On Wednesday, Tory shadow home secretary David Davis described the house arrest plans as "public internment".
He told MPs: "We know that throughout history internment has generally backfired, because of the resentment that it creates, so unless the process is clearly just, the home secretary could find himself confining one known terrorist only to recruit for our enemies 10 unknown terrorists."