Harriet Harman pledges Labour unity in support of Ed Miliband

Harriet Harman today pulled down the curtain on a "roller-coaster" Labour conference which has seen the party gain a new leader and lose one of its brightest stars.

In the deputy leader's traditional end-of conference address before the singing of the Red Flag, she told delegates: "The contest for the leadership is over. The contest for the future of the country begins."

Ms Harman - who returned to her position as deputy on Ed Miliband's election on Saturday after four months at the helm of the party - said the new leader was "intelligent, courageous and he has a good heart".

"We will all be united in support of him and I have no doubt he will be a great Labour leader of our party," she said.

She also praised Mr Miliband's brother and defeated leadership rival David, who stepped down from the Labour frontbenches yesterday, as "a towering figure in our party".

In a hint that she may expect him eventually to return to the frontline of politics, she said: "The Labour Party is proud of him. We are proud of what he did in government. And I know we will be proud of what he does in the future."

At the end of a week dominated by the drama of Ed's knife-edge victory and uncertainty about David's future, she told delegates: "This has been a historic conference. It's been a roller-coaster of emotions.

"We're disappointed to be in opposition, but proud of what we achieved in government. We are sobered by the scale of the challenge that lies ahead, but fortified by the energy and determination of our new leader, Ed Miliband."

And she joked Mr Miliband's declaration that a "new generation" was taking charge also included people like her who were "a new generation of fabulous older women".

Prime Minister David Cameron today hit out at Mr Miliband, warning that his refusal to face up to the problems of Britain's record deficit was "completely betraying" the country's national interest.

In his speech on Tuesday, the Labour leader accused Mr Cameron of using the need to cut the deficit as a justification for imposing a "miserable, pessimistic" future on Britain. While Labour was "serious about reducing our deficit", it would do so in a way that prioritises growth and supports jobs, he said.

But Mr Cameron told ITV1's This Morning today: "To say what Ed Miliband has said, to say 'forget about the deficit' because it is somehow pessimistic to talk about it, that would be completely betraying the country.

"If you are trying to do this job properly it is not about being popular, it is about trying to do what is right."

Asked if he was pleased to face Ed rather than David Miliband across the despatch box, the Prime Minister said he did not know either of them "that well".

"I take all my opponents very seriously, you have got to," he said.

He said he had offered, in a congratulatory phone call to Mr Miliband in the wake of Saturday's leadership vote, to cooperate where possible with the Opposition.

Prime Minister's Questions would be "a great ding-dong" but "sometimes it is right that we should be talking together on behalf of the nation, agreeing how to handle sensitive issues", he added.

Mr Miliband has said he will lead a "responsible" Opposition which will not oppose every cut and is ready to support the Government where it is taking action he believes is right, such as cutting back on short prison sentences or reviewing stop and search laws.

Labour's attention now turns to the composition of the new shadow cabinet, with ballot papers being distributed among MPs from today.

Thanks to rules approved by the Parliamentary Labour Party earlier this month, the new leader does not have a free hand in the selection of his top team, but must distribute jobs among those voted in by his fellow-MPs.

After he secured the first-preference votes of just 84 of Labour's 257 MPs, Mr Miliband's supporters will almost certainly be in a minority around the shadow cabinet table, and one of his first big challenges will be to impose his authority and forge unity behind his agenda.

His team will inevitably include several Blairites who are less than enthusiastic about his aim to "turn the page on New Labour" and would have preferred David as leader.

The former foreign secretary announced last night that he was quitting the frontbench to avoid becoming a "distraction" to the new leader, adding it would also allow him to "recharge my political and intellectual batteries" and spend more time with his family.

He remains MP for South Shields, and has made clear he is not ruling out a return to the frontbench - and Ed said he was keeping the door open for him.

Some 49 Labour MPs, ranging from former cabinet ministers like Alan Johnson, Ed Balls and Peter Hain to relatively unknown backbenchers, are standing for 19 elected shadow cabinet positions in a ballot of MPs which concludes next Thursday. Ms Harman and new chief whip Rosie Winterton also take places by virtue of their positions.

Along with the elder Miliband brother, some of the biggest figures in the former Labour administration are taking their exit from the front benches, with Alistair Darling, Margaret Beckett, Jack Straw and Bob Ainsworth all standing down.