Samantha Cameron appeared in the BBC film briefly and made it clear she hoped her husband would remain at Number 10. She told the BBC: "He is definitely in my mind the best man for the job."

And she added: "I hope me and the children help him keep things in perspective, keep him grounded, help him pace himself over the next eight weeks."

And Mr Cameron paid tribute to his wife for keeping him "sane" in Downing Street, and revealed she will be playing a role in the Conservative election campaign.

"The fact that we do different things helps actually," he said. "She keeps me sane because she's one of the most organised people that I've ever come across, so home life, the children's life, everything is just brilliantly organised.

"Otherwise you wouldn't get this family time - unless you're really well organised everything would be blown off course, you wouldn't get the chance. She's amazing like that."

The Prime Minister was interviewed by the BBC's deputy political editor James Landale in a series of profiles designed to show the private side of party leaders. He was seen cheering on son Elwen's football team from the sidelines, shopping in the local butcher's shop and preparing food in the kitchen of his Oxfordshire home.

House of Commons
Parliament

Back in the Commons, another former Chancellor, Alistair Darling, made what he said would be his final speech in the House of Commons. To laughter form the Labour benches he highlighted part of the Office of Budgetary Responsibility's report on the Budget, which found that it "is not expected to have any material impact on the economy".

"I thought that was what Budgets are for," he said.

The economy was growing in 2010 "because of the measures we put in place in 2008 and 2009 to stop a recession becoming a depression", whereas the government's interventions have only led to the economy "slowing down" meaning increased borrowing, according to Mr Darling.

Image source, PA

Labour and the Conservatives are neck-and-neck while support for UKIP is falling, according to latest polling by Lord Ashcroft.

The Tory peer's national snapshot puts the two largest parties on 33%, with Labour up four points on last week and the Conservatives up by two. UKIP dropped three points to 12% and the Green Party fell by the same amount to 5% while the SNP went up one point to 6% and the Liberal Democrats remained on 8%, the survey found.

Lord Ashcroft said: "Last week's Budget appears to have had no overall impact on people's assessment of whom to trust with the economy".

Deborah Orgill, Warwickshire: An unwise thing to say. Tony Blair said a similar thing and regretted it. The future has unseen twists and turns which means the things we say today may not be what we would decide tomorrow.

The Spectator

"In a brave move, David Cameron sets fire to his authority" says Alex Massie in this blog post, external. "No, I don't know why David Cameron would amputate his authority before he runs for re-election either."

tweets:, external Half of electorate think Cameron should serve full term if re-elected compared to only one in four who think he should step down before then

tweets:, external So the man who didn't quite win his 1st election and hasn't yet won his 2nd election now says he won't contest a third? That where we are?

tweets:, external Not sure this was quite what Dave had in mind when he invited the Beeb in for a cosy kitchen-side interview with the family

tweets:, external I'm surprised Cameron's made the same mistake as Blair..A full term and no more. Blair lost authority from the moment he uttered the words.

tweets:, external Post-Cam BBC interview, a friend of Boris Johnson says he is "focused on being low key and loyal" and "not in the business of early coups".

tweets:, external Tory MP texts me: "Well done Dave. What the Tory party needs right now is a leadership contest."

@gallaghereditor

tweets:, external Genuine scoop for @BBCJLandale - first time in living memory I've been stopped short by BBC news

tweets:, external Every hack in Westminster expected Cameron to stand down in 2018. Not one of them expected him to say so publicly.

tweets:, external Vote Cameron get Osborne? Vote Cameron get May? Vote Cameron get Johnson? Vote Cameron get Javid? Vote Cameron get Hammond?

David Cameron was interviewed after watching his son play football.

tweets:, external Am puzzled by the political theory behind David Cameron's "no third term" pledge. How does he / the Tories benefit?

tweets:, external Nigel Farage reaction to Cameron "This will create long-awaited civil war in Conservative party over Europe!" #UKIP

tweets:, external Cameron says would serve full term to 2020 but wouldn't another leader have to lead election campaign ? so contest in Autumn 2019? #GE2015

James Landale
Deputy Political Editor, BBC News

James Landale, reporting from outside Number 10, said: "By being specific, he has opened up a Pandora's Box. On timings, would he stand at the next election and then stand down? What would it mean for the three successors [Theresa May, George Osborne and Boris Johnson]? He has invited the political world and the country to start to think about a time when he will no longer be in there [Number 10]. That's quite risky."

tweets:, external How should Labour handle this Cameron self-imposed term limit? "Vote Dave, Get Boris"? No, that's too appealing isn't it...