Tony Blair was today accused of "wasting police time" after the Home Office confirmed that it is halting plans to force England's police forces to merge, marking the end of the biggest reform of the service for 40 years.

In a dramatic U-turn, Tony McNulty, the Police Minister, conceded that the ?1 billion programme would not go ahead, although the Government would retain powers to force amalgamations as an "absolute last resort".

The announcement produced lively exchanges at Prime Minister's Question Time with David Cameron, the Conservative leader, accusing Tony Blair of "wasting police time".

"The flagship of forced mergers has sunk without trace," said Mr Cameron.
 
Mr Blair insisted that mergers were "not off the agenda" since it was still important in some parts of the country to have capability that crossed force lines. However, there was no need to enforce mergers, said Mr Blair.

The Times revealed on Tuesday that the Home Office had abandoned its plans after the voluntary merger of the Lancashire and Cumbria forces collapsed because there was no money to finance the deal. Lancashire and Cumbria were the only forces that wanted to merge.

The move brought an angry outburst from former Home Secretary Charles Clarke, the architect of the reforms. He said it would damage the ability of the police to tackle terrorism and organised crime.

But today Mr McNulty told police authority members: "Are the mergers going to go through in one way or another eventually? "I think the definitive answer to that is ?No?." The minister said that the police restructuring could now take years to complete.

He said: "I do say that the Government should still hold that as a power (enforced mergers) and should take much debate and discussion over the next few years. "As an absolutely last resort, that should still be there."

Mr McNulty said later that he had misunderstood the question he was asked in the conference, and had believed he was being asked whether enforced mergers would now not take place.

He said that police forces had now been asked to discuss with the Home Office alternative ways of meeting the demands of modern policing.

A report by the Her Majesty's Inspectorate of Constabulary (HMIC) in September 2005, entitled Closing the Gap, found there were "significant weaknesses" in some forces' abilities to deal with major terrorist or domestic incidents.

The Conservatives and Liberal Democrats had both opposed the merger plans.