Her remarks in a speech in Malaysia came only hours after the Prime Minister promised to tighten anti-terrorist legislation in the wake of the London bombings and he urged the opposition parties not to block them on the grounds that they would restrict traditional freedoms.
Although Mr Blair is expected to reject proposals by the Association of Chief Police Officers (Acpo) for suspected terrorists to be detained for up to three months, he is ready to allow the police to extend the present 14-day limit if they can convince a judge that further evidence is likely to be forthcoming over the next 14-day period.
Mr Blair has asked the Home Office to produce several options by September. Government sources said yesterday that renewable 14-day periods was a leading option but no decision had yet been taken on whether they could be renewed for a maximum of one, two or three months.
Downing Street denied embarrassment over Mrs Blair's speech, saying: "She was speaking in her capacity as a human rights lawyer. What she says in private is a matter for her." But, privately, some ministers called her comments unfortunate, one saying: "Her sense of timing is impeccable."
Although many Labour MPs share her concerns on civil liberties, they have become increasingly worried her actions have damaged the Government. Last month, controversy surrounded her being paid a reported £20,000 for a speech in Washington which coincided with Mr Blair's visit to President George Bush.
One Labour MP said: "There was talk of Tony being liberated because he doesn't have to fight another election. It seems she feels liberated too."
Patrick Mercer, the Tory spokesman on homeland security, said: "Cherie Blair or Cherie Booth, whichever name she's going under just at the moment, is entitled to her private opinions of course and to express those. But she is the Prime Minister's wife and I think this is a desperately insensitive time for her to be making those sorts of comments."
Mr Blair said yesterday: "I think I have said it is important that we balance these things, civil liberties for people. It is very important to protect our way of life and it is important to protect our security. I think probably, to be fair, if you read the whole of the speech, she was saying the same thing."
But the Prime Minister and his wife appear to look at the issue from different ends of the telescope. In February, when the Government was trying to push its control orders through parliament, Mr Blair said: "Considerations of national security have to come before civil liberties, no matter how important those civil liberties are."
Mrs Blair, in her speech, praised a "landmark ruling" by the law lords last December against the provision in the Government's Anti-Terrorism, Crime and Security Act allowing terrorist suspects to be locked up indefinitely. At a press conference the same day, Mr Blair criticised the remarks by one of the law lords who made the ruling.
Mrs Blair said then: "What the case makes clear is that the Government, even in times when there is a threat to national security, must act strictly in accordance with the law."
On the London bombings, she said: "Nothing I could say here could possibly be construed as making light of these horrific acts of violence, or of the responsibility imposed on the UK and other governments to keep the public safe, or of the difficult and dangerous task performed by the police and intelligence services.
"At the same time, it is all too easy for us to respond to such terror in a way which undermines commitment to our most deeply held values and convictions and which cheapens our right to call ourselves a civilised nation."Reuse content