Tony Blair was affected twice by the problem of a pounding heart during Prime Minister’s Questions in 2004 and was unwell throughout much of that year, it was disclosed today.

Blair Unbound reveals that Mr Blair regularly asked himself in 2004 whether he should stay in office. Weighed down by the Iraq war aftermath, the Hutton inquiry, a constant war of attrition with Gordon Brown, worries over his family as well as his own health, he questioned whether he would be able to command the domestic agenda or achieve his ambitions.

The book tells how Mr Blair’s job took a toll on all his family. From 1997 to 2002 the children basked in having a popular, charismatic father. The Iraq war changed that and it was never easy for the children if their father was unpopular and under attack.

During the spring of 2004 Leo, the youngest, was not sleeping well, which meant many broken nights for the Blairs. The night that he came back from a European summit in March Leo had woken up and got into his parents’ bed. Mr Blair could not sleep and climbed into Leo’s nursery bed but was still exhausted in the morning. The problems made Cherie, his most stalwart support, wonder whether remaining at No 10 was really worthwhile, according to friends. After a particularly bloody Parliamentary Labour Party meeting “those close to him began to wonder how much more punishment he could take”.

On October 19, 2003, Mr Blair had been rushed to hospital after complaining of chest pains while at Chequers, and doctors diagnosed an irregular heartbeat. He had an emergency cardioversion and stayed in hospital for five hours before going to No 10.

The official bulletin said that there was no reason why the condition should recur and Mr Blair was blasé about it. But friends confirmed that his heart continued to trouble him. “He felt unwell quite a lot during the year that followed, one confidant said. “After he told me, I began to watch him carefully. He was generally not very well in 2004.” He would feel his heart beginning to pound and it made him feel “strange and disconcerted”. Though no one spotted it, the pounding happened twice during PMQs in 2004, the book reveals.

On the day he announced that he would fight the 2005 election but not the next one, and that he had bought a £3.6 million house in Connaught Square, Mr Blair also said that he would be going into hospital on October 1 to have an operation to eliminate his irregular heartbeat. It was to succeed and Mr Blair’s health was not an issue during the remaining years of his premiership.

But in that spring of 2004 Mr Blair was despondent and “wobbled” about staying. He missed his key advisers, Anji Hunter and Alastair Campbell, who had moved on, and his friends sensed a growing sense of isolation. They organised numerous dinners at Chequers, in the flat at No 10 or in their own homes to remind him that they “were there for him”.

At different times Mr Campbell and Ms Hunter advised him to follow their example and leave No 10. But Sally Morgan and Jonathan Powell were staunch; he must stay.

Most significant of all was Cherie Blair. “She’s always been massively in favour of him staying on. She’s never wanted to pack it in and that’s why she’s so furious with Gordon Brown,” John Burton, Mr Blair’s agent and close friend, said. “Cherie couldn’t stand the neighbour,” a senior official said. “She begged Tony to stay on. She simply couldn’t bear the prospect of Brown taking over.”

Lord Turnbull, who was Cabinet Secretary from 2002 to 2005, said: “The wobble was not visible to me at the time. It was only when I read about it in the press that I knew what might be happening.”

Panic gripped No 10 for a short time while aides speed-read the Hutton report into the death of David Kelly, the government scientist, the book reveals.

No 10 received the report, which was crucial to the survival of Tony Blair, at midday on January 27, 2004, a day before it was published. This gave aides 24 hours to prepare the Prime Minister’s response. Teams spread out around No 10 to examine different parts of the report. The idea was to reconvene in the Cabinet Room at 3pm.

Yellow and pink highlighter pens were given out, yellow to highlight the positive passages and pink for the negative ones.

But Jonathan Powell, Mr Blair’s chief of staff, confused his pinks and yellows. Which meant that when staff arrived in the Cabinet Room to see his marked-up copy consternation set in. But it was short-lived and the general feeling about the report was relief.

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