By Ian Dunt

Gordon Brown has finally confirmed the rumours of a disastrously bad-tempered relationship with Tony Blair.

Speaking during a gruelling and personal interview with Piers Morgan to be broadcast over the weekend, the prime minister also suggested he should have been the one to lead the Labour party when John Smith died.

"I believed I could do the job, I believed that I'd got the experience and built up the experience to do it," he said.

Brown vs Morgan: The transcript

"I don't deny that, that there were fights about different issues but it's always the case.

"In fact it's better to be open and honest and say there were disagreements about certain things but at the same time we managed, I think in the national interest, to get things sorted out."

But he conceded their relationship has been "incredibly difficult".

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Speaking about the famous meeting in the Granita restaurant, where the two men allegedly formulated a handover plan, Mr Brown said: "I'd already agreed with Tony before that dinner that he would stand for the leadership and I would stay on as the shadow chancellor, as the person in charge of economic policy.

"And there's an understanding that at some point Tony would stand down and he would support me if, when, that was the case. And that's where we left it."

The most moving part of the interview - heavily trailed before broadcast - relates to Mr Brown's thoughts on the death of his daughter.

"Nobody actually really told us for a week, it just gradually dawned on us that, that something was going wrong and she wasn't getting bigger, she wasn't growing and, no matter what treatment that was being given to her, she wasn't able to respond to it," he said.

"And I could hold her hand and I could feel that she knew I was there and there was nothing that you could see that was actually wrong, but she just wasn't growing.

"And then probably after a week Sarah and I... she was in the special care. I turned to the doctor and I said: 'She's not going to live, is she?'

"And he said: 'No, I don't think so. She's not going to live'."

Mr Brown then went on to praise his wife, saying: "Sarah and I, we're a modern love story. We have been very fortunate. She is beautiful, she's elegant, she's compassionate, she's dignified, I'm very, very proud of her."

The interview will have been tough going for the prime minister, who has previously attempted to keep his private life private. Barring introductions from his wife at the Labour conference the last two years, Mr Brown has been notable for keeping his family out of the public eye, unlike Tory leader David Cameron whose comfort with letting the cameras into his home has been one of the defining characteristics of his leadership.

He will have struggled with some of Mr Morgan's more puerile questions, including one asking the prime minister if he had joined "the mile high club".

Nick Clegg is still trying to get over his Nick "Cleggover" nickname after confessing in an interview with mr Morgan that he had slept with around 30 women.

ITV1's Piers Morgan's Life Stories interview with Mr Brown will be shown on Valentine's Day.