Gordon Brown faced a grilling from all parties on today's upcoming pre-charge detention vote in this week's PMQs.
MPs are set to vote on whether to raise the maximum limit for terror suspects' pre-charge detention from 28 to 42 days from 18:00 BST.
The Conservatives are indicating they are expecting the government will win through, but David Cameron sought to rack up the points against Mr Brown and continue his good form of recent weeks.
The session was kicked off by Mr Brown defending the accusation that he was the least popular prime minister ever.
"I will leave the schoolboy politics to him," the prime minister replied, pointing out that he might have done better on a day debating national security.
He was then questioned about 42 days and the relationship between the government and security services, arguing 28 days is not enough when it comes to the biggest plots.
Mr Cameron then stepped up to the despatch box. After the usual sombre preliminaries about fallen British servicemen, he surprised MPs with a question about the situation in Afghanistan.
The attempt to wrongfoot the prime minister failed as Mr Brown continued the solemnities. "We are making progress in training the Afghan army... and in building economic and social development in the country," he said, pointing to the 70 per cent turnout in the last elections. "This is a long haul - but our duty is to stop the Taliban ever regaining power."
The opposition leader expressed concern that, while doing well militarily, the situation was less positive in other aspects. He called on Mr Brown to make more "regular updates" to keep the British people onside.
"I'm very happy to give regular updates," Mr Brown replied. "Nobody is saying the position in Afghanistan is easy. But last year... the number of poppy-free provinces doubled to 13. It is not a case of things going backward - it is a case of us seeing progress."
After a lengthy lecture on the issue Mr Cameron turned to the issue of 42 days. "This is an enormous step to take and we need the strongest possible evidence." He pointed to doubts from the director of public prosecutions to show uncertainty from within the government.
As usual, Mr Brown said he had taken enough evidence to show 42 days is "the right thing to do". He appealed to concerns about national security and pointed to police chiefs Ken Jones, Hugh Orde and Lord Stevens to demonstrate his point. "In a moment of calm we should put in place this legislation. I do not want in a moment of panic to come to the house and bring emergency legislation."
Mr Cameron pointed out this is exactly what will happen under the concessions. "The PM would have a genuine argument if he had lined up a phalanx... [of senior figures] in favour of this case - but he hasn't. He hasn't made the case this is unnecessary."
He then suggested the move may even be "counter-productive", warning: "Aren't we making a bad step? When we trash our liberties, aren't we doing our work for them?"
As usual, the prime minister's strategy was to be long-term. "It is no use opposition for opposition's sake," he said, warning this must happen "in sorrow rather than anger".
Mr Cameron bristled in response, pointing out the Conservatives needed no advice on fighting terrorism.
"We're not going to fight terrorism effectively if we undermine our liberties," he continued, moving on to the proposal of parliamentary debate. He expressed concerns that the practicalities of how such a debate might occur had not been properly thought out.
"Shouldn't every MP in this house be thinking this is not about the future of the prime minister, this is about our liberties and they should vote with their consciences," he said.
After a brief interruption by the Speaker, Mr Brown cited the Conservative party members' website which contradicted Mr Cameron's position. Mr Cameron said "that last bit was so below the level of debate" in response.
"If the prime minister is saying that it is popular to announce you're going to bang up terrorist suspects... it is popular," he said, before positioning himself as above populist concerns by insisting "you have to do what is right".
He accused Mr Brown of "ineffective authoritarianism" and said the "supposedly progressive prime minister should come down on the side of civil liberty".
"We have, Mr Speaker," Mr Brown replied, listing the concessions already made by the government on the issue. "We should be facing up to an issue of national security. I would like to have achieved a consensus above party politics. Because it has not been possible to do so the government has to make a judgement - not because it is popular but because it is right."
Liberal Democrat Nick Clegg did not give the prime minister any relief on the issue, asking him about the covert intelligence issue and its practicalities relating to cases being considered by the Commons.
Mr Brown said it would be for the house to vote on whether a grave and exceptional terrorist threat has occurred. "I would hope that it is exactly the same issue that would be faced in the Civil Contingencies Act."
Mr Clegg said the proposal would be blocked in the House of Lords and that it would face legal challenges from Europe. He accused Mr Brown of "playing politics with our liberties" and said the bill would "never reach the statute book".
The prime minister reacted with incredulity to this suggestion. "It is not only popular, it is also necessary and right and there are many people who disagree with him profoundly."
Labour backbencher Tim Sheridan asked for reassurance that the civil liberties of "decent hardworking families" would not be impinged by the bill, in militant support of the prime minister.
"He is absolutely right," a grateful Mr Brown responded. "It is stated clearly in the bill it is a reserve power. The protections for civil liberties that are built into this bill... are the greatest we have seen when dealing with terrorist threats."
A past horror for the government then re-emerged as a Conservative backbencher asked about 10p income tax. Mr Brown said the Commons was not interested in listening to Tories "lecturing us" about what to do about the low-paid.
Sylvia Barlow raised national carers' week, asking Mr Brown for extra measures about elderly carers. The prime minister said the six million people giving up their time to care for relatives, friends or neighbours.
The issue of a referendum on the Lisbon treaty, going to the vote in the Lords later today was then raised. "It is not a fundamental change in the constitutional arrangement," Mr Brown said.
Dawn Butler publicised an online discussion forum for young people, mylifemysay.co.uk. She asked about swimming for young people. "As we look to provide youth centres in this country we are looking at the dormant accounts in building societies. We believe there are substantial funds that should be made available. We want to use these funds to transform youth facilities in every constituency in the country."
Former Tory leader Michael Howard was next up, returning to 42 days yet again. He asked: "Can he explain how this House could debate and vote upon the detention without charge of a person for up to six weeks without prejudicing any subsequent trial of that person?"
Mr Brown said Mr Howard "knows a lot about not answering questions", to barracking from both sides of the Commons. He then said Mr Howard had "misunderstood the legislation".
The Lib Dems' Paul Burstow asked Mr Brown about dementia and whether he would take action to close legal loopholes about elderly abuse. The prime minister said the issue would fall into the remit of an NHS constitution, which is about to be proposed.
Schools secretary Ed Balls faced pressure from a Labour backbencher about the national challenge scheme, seeking reassurance that the intention is to avoid closures, not force them.
The prime minister said the government was determined to "improve results" and "make schools better". "More money is being injected into the schools system to make possible this increase in standards."
Pete Wishart asked Mr Brown about the price of North Sea oil and complained that Scotland was being left out of the higher prices. "Surely with this windfall it's time for a Scottish oil fund?"
The prime minister responded: "We are one United Kingdom and we share the risks, the rewards, the resources. Scotland has never been better off as a result of the Labour government."