Opposition parties gave short shrift this morning to the latest attempt by the Government to win support for its plan to double the time that terrorist suspects can be held without charge.

The BBC confirmed reports in The Times and other newspapers dating back to the middle of last month that ministers are talking privately of raising to limit to as much as 58 days from the current 28 days.

The choice of 58 days is purely because David Davis, the Shadow Home Secretary, and the Liberty pressure group have suggested that that option already exists - by adding the 30 days available under emergency powers legislation to the existing limit.

As Gordon Brown told the Commons yesterday, the Government is trying to seek a consensus with the Opposition on the rare circumstances in which the 28-day limit could be exceeded - including oversight from judges, parliament, the Director of Public Prosecutions and the independent terrorism reviewer.

But the Prime Minister's case was not helped by remarks from his own security minister, the former Royal Navy chief Admiral Lord West of Spithead, that he had yet to be convinced on the need for longer detentions.

The suspicion at Westminster is that Mr Brown is trying to divide the Opposition forces by moving the argument onto their territory. Under the plan floated this morning, the Home Secretary would have the power to approve the extensions but only after going through all the hoops set out by Mr Brown.

Mr Davis said there was “no evidence whatsoever” to support an extension and said the Government was motivated by politics, not national security.

“The only circumstance under which we could imagine a problem being posed to a Government they couldn’t deal with would be a series of massive attacks - five attacks all at once, five alleged Heathrow plots all at once,” he told BBC Radio 4's Today programme.

“We said to them ’you’ve already got the power, you created it before, it’s called the Civil Contingencies Act, you declare a state of emergency’.

“If you need special measures, you have a declared, temporary state of emergency. What the Government is looking for is an undeclared, permanent state of emergency and we’re not having it.”

Mr Davis added that opposition parties had been “bending over backwards” to help find a solution.

“This is a problem for the Government. They cannot persuade their own rebels that they need more than 28 days. We know the whips have been trying to pressurise them and now they are trying to come up with something else which they think sounds good. But the raw truth is there is no evidence whatsoever for going beyond 28 days as we stand.

"We have been bending over backwards for the last several months to try to get a practical outcome the Government can live with, get them off the hook they have impaled themselves on. The raw truth is they have been unwilling to accept the most reasonable and sensible proposals.

He also rejected suggestions that declaring a state of emergency would create panic.

“Panic the nation? Are you joking? This is a nation that had 3,000 deaths under the IRA campaign. It had 3,000 deaths in one day at the height of the Blitz,” he said.

Nick Clegg, the Liberal Democrat home affairs spokesman, added: “So much for a cross-party approach to terrorism. This looks suspiciously like a desperate attempt by the Government to cover its tracks after yesterday’s lamentable display of mixed messages.

“How does Gordon Brown seriously think he can forge a national consensus on such a vital issue without any new evidence and with utter disregard for the strong opinions of those who believe it would be a step too far?”

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