Tony Blair has described his relationship with Gordon Brown as like a "marriage".

The prime minister told the News of the World on Sunday that his close working relationship with the chancellor would continue in a Labour third term.

Brown has returned to the forefront of Labour's election campaign in recent weeks in a sign that he has put aside his well-reported differences with Blair for the good of the party.

The two key architects of New Labour have fallen out over the direction of government policy on the public services, the appointment of Alan Milburn as head of the Labour campaign and Blair's promise to serve another full parliament if re-elected as prime minister.

But Blair has heaped praise on his colleagues' handling of the economy in a series of joint appearances in the first days of the campaign.

However he also acknowledged that they have had their differences.

"When you become PM and chancellor these are the two big jobs in government," he said.

"Of course you'll have things that you'll discuss and occasionally you can disagree.

"But the basic belief that motivates the two of us is the same. You come into the Labour Party because you believe in a fairer society.

"So the personal bond, like a marriage, is also a political bond."

And in the same interview Brown added that the relationship established when both men were first elected as MPs in 1983 would endure.

"When you've known someone for 22 years, and you've had to work out problems together, you do have a bond," the chancellor said.

Milburn

Meanwhile Milburn denied that Brown had "taken over" the Labour campaign.

The campaign co-ordinator has been criticised for the election effort's faltering start but insisted it was always planned for the chancellor to play a bigger role than he did before the Budget.

"I am still the co-ordinator. He has not taken over," Milburn told the BBC's Politics Show.

"As I have said, and Tony Blair has said right from the outset of this, Gordon is obviously going to be playing a big part in this campaign.

"Why? For a simple reason. The economy is going to be absolutely centre-stage, at least in the Labour campaign.

"It's interesting that the Tories, the one thing they are not talking about is the issue that in the end most people are bothered about, which is the strength and stability of the economy and whether we keep it like that."

Succession

The Sunday papers also carried a range of stories on how and if Brown will take over from Blair during a third term.

The prime minister is said to have accepted that the chancellor will succeed him when he steps down and agreed to back him.

Scotland on Sunday suggested that Brown's path would be eased by a change in Labour's internal election rules, raising the threshold of MPs and peers required to back a leadership nomination from one eighth to one fifth.

That would make it harder for rivals to challenge Brown and would be likely to narrow the field to a "left" and "right" candidate.

However the Mail on Sunday reported that Blair could stay on as prime minister through a full parliament while Brown took over the party leadership.

A handover period would allow Blair to keep his promise of serving a full third term, without stopping Brown from fighting a fourth term election campaign on his own terms.