UK cops seek tough new powers

Senior officers also want powers to attack and close down websites, and a new criminal offence of using the internet to prepare acts of terrorism, to "suppress inappropriate internet usage".

They also want to make it a criminal offence for suspects to refuse to cooperate in giving the police full access to computer files by refusing to disclose their encryption keys.

The police would also like to see much clearer information given to the public about the threat level, the creation of a specialist border security agency and further discussions about the use of phonetap evidence in terrorist cases.

The Association of Chief Police Officers published its list of 11 further changes in the law it wants after meeting Mr Blair and security services chiefs yesterday.

MI5 and MI6 wanted yesterday's meeting to discuss Britain's entire counter-terrorism strategy and how to fill the intelligence gaps exposed by the London bombings.

Whitehall officials confirmed that, as reported in yesterday's Guardian, the security and intelligence agencies want a new system of plea bargaining. Convicted terrorists would be given lighter sentences if they supplied information before their trials.

Suspects would be given the chance to provide information in "intelligence-only" interviews and none of the information would be used against them in trials.

Officials also said MI5 was "in principle" in favour of the product of phone taps being used as evidence in trials.