PM refuses to authorise telephone-tap evidence

The Independent has learnt the Prime Minister has bowed to opposition to the move by intelligence chiefs in MI6 and MI5 and told colleagues that he will not change the law.

MI6 and MI5 told the Prime Minister at a Downing Street terrorist summit they will use an increase in resources to expand intelligence units in the north of England, including West Yorkshire, where three of the London bombers lived.

Mr Blair signalled he is prepared to increase spending by the Metropolitan Police to counter the threat of terrorism in the capital. MI6 and MI5 chiefs assured Mr Blair they had the resources to deal with the terrorist attacks, but warned that their surveillance of suspected terrorists by telephone tapping and a wide range of other means would be compromised if they were forced to produce their evidence to the suspects' defence lawyers in court.

The Association of Chief Police Officers (Acpo) said it was willing to allow more discussion of the change in the law to allow intelligence intercepts. However, the Home Secretary, Charles Clarke, made it clear he believed there was a misconception that it would lead to more convictions.

"It's more complicated than people think," said a senior ministerial source. "Evidence from microphones and call data are admissible. One of our difficulties is you cannot explain some of the complexity without revealing some of our methods. I am surprised the Conservatives are spending time on it. If we could do it, we would do it."

Mr Blair hinted that he would favour the use of intercept evidence by the intelligence services in court for the first time during Prime Minister's Questions. The Tory leader, Michael Howard, has campaigned for intercept evidence to be used in court.

Mr Clarke also rejected a demand by Acpo for the maximum detention time without charge for terrorist suspects to be increase from 14 days to three months.

Yesterday Mr Blair was briefed by conference call at Chequers by Sir Ian Blair, the Metropolitan Police Commissioner, and Eliza Manningham-Buller, the head of MI5. He will stay at Chequers this week to underline his determination to let the security services handle the terrorist crisis.