I personally need to think about that at great length and I will

David Blunkett

He said: "Those things are very difficult issues but they are ones we are going to have to address if we are actually going to protect the most basic freedom of all which is to live in peace without fear," he said.

But the suggestion that ID cards could be introduced drew short shrift from the director of the civil rights group Liberty who fears that they would leave minorities open to victimisation by the authorities.

Mr Blunkett said he did not want to discuss identity cards so soon after the terror attack in the US before adding: "That is something undoubtedly that is not going to go away.

"I personally need to think about that at great length and I will."

Mr Blunkett told BBC Radio 4's Today programme that he would return to the issue later in the year.

But John Wadham, the director of Liberty said: "I think if we look at some of the ideas being suggested - for instance identity cards - we did have them in World War Two.

Churchill

"They were abolished by Winston Churchill's government [because] in order for identity cards to be effective what we have to do is give the police and others powers to demand to see them and they have to demand to see those identity cards very regularly of all of us in order to have any real effect," he told Radio 4's World at One programme.

Mr Wadham also expressed the fear that certain groups might be singled out such as foreigners, ethnic minorities and "people who are seen to be not respectable".

During the emergency Commons debate on the atrocities in New York and Washington Tory MP Dr Julian Lewis urged the introduction of a national identity card scheme.

Draconian

He said that two relatives of one of his constituents were thought to have died in the attacks on the World Trade Center and he told MPs that extreme measures were necessary.

"If all this sounds draconian it is precisely because those are the measures that open societies have to take when they are under attack."

He added that an act of war had been perpetrated and people should consider whether any measures in response should still be considered by peace time standards "or by the standards that obtain when a country is fighting to preserve its life."