Nicolas Sarkozy emerged from the Downing Street dining room with Tony Blair and announced to his aides: “Tony and I have just taken a decision. We’re going to conquer Europe.”

The scene appears in an intimate portrait of Mr Sarkozy’s march to power that is expected to cause a sensation with its dissection of the French President’s Napoleonic personality.

Super-Sarko is vain, self-obsessed and cruel but he also shows a vulnerable, childlike side, along with an absolute confidence in his own judgment, according to Yasmina Reza, France’s most celebrated playwright.

In a calculated risk, Mr Sarkozy invited Reza to accompany him from last September through to his installation in the Elysée Palace in May. The playwright pulls few punches in her book,L’Aube, le Soir ou la Nuit (Dawn, Evening or the Night), published tomorrow. But she also shows affection for the “boyish” President.

Her close-up of Sarko confirms what France already knows, or suspects, of its hyper-driven leader. He is perpetually impatient, contemptuous and sentimental. He feigns interest in public appearances that bore him stiff.

In bursts of temper, he routinely calls his own camp, as well as his adversaries, a***holes. During the campaign he referred to Ségolène Royal, his Socialist opponent, as “une pauvre conne” (poor stupid cow) who had “gone round the twist”.

Unlike the respectful media, Reza dwells on the short stature that makes Mr Sarkozy invisible in a crowd. “I get the impression that I am seeing a little boy,” she writes. “I am struck often by his childishness,” she says. “He smiles in the gauche way of a child showing off his present.”

In one scene he shows off his Rolex watch. In another, euphoric on the verge of the presidency, he relishes his imminent official lodgings: “I’m going to get a palace in Paris, a château at Rambouillet and a fort at Brégançon. C’est la vie.” He is amazed that show-biz stars such as Johnny Hallyday, the French rock veteran, have become his friends. Reza also notes something that no French media have remarked on; Mr Sarkozy always walks with a slight limp.

Yet she also talks of her “unbounded admiration” for the independent spirit of the outsider who tells her that the presidency brought him no joy but great relief. “He owes nothing to anyone and he knows it,” she writes.

Reza’s book was published amid secrecy with an initial 100,000 print run. It is a certain bestseller and already being tipped for this autumn’s Prix Goncourt, the top French literary award. Reza has won numerous prizes, including Olivier and Evening Standard awards for Art, which was a long-running hit in the West End of London as well as Broadway. Le Parisien newspaper called her book a “fabulous portrait of a singular man”.

Reza reveals little about Mr Sarkozy’s private life and bumpy marriage but she offers telling glimpses of the candidate’s forays abroad. In London Mr Sarkozy is thrilled by his lunch with Mr Blair. “Nobody listening who shouldn’t be?” Mr Sarkozy checks before making his announcement about Europe.

After election, Mr Sarkozy coopted Mr Blair in his successful effort to persuade Angela Merkel, the German Chancellor, to accept a boiled-down version of the defunct European Constitution.

In London Mr Sarkozy, a teetotaller and fitness buff, confided that he does not admire Winston Churchill. Reza interprets this to be disapproval of Churchill’s heavy-drinking life.

In Washington last autumn Mr Sarkozy received revealing advice from Jean-David Levitte, the French ambassador whom he has appointed as his security adviser. When meeting President Bush, he should do as Mrs Merkel and show friendship, Mr Levitte said. “You will find him strong and welcoming but behind the façade you will find a man in a state of distress.”

Reza focuses on Mr Sarkozy’s long campaign to impose himself on an Establishment that regarded him as an upstart immigrant’s son. He tells New York Jewish leaders not to believe what they read about him. “Part of the French elite hates me much more than they hate Israel or the Americans,” Reza quotes him as saying. During the campaign, Mr Sarkozy takes pleasure in putting down President Chirac, the mentor against whom he rebelled, when Mr Chirac telephones to tell him that he believes he will win. “I told him: ‘You’ve been calling me for six months to tell me that you’re worried. I did not believe you then and I don’t believe you now either’,” Mr Sarkozy says.

He most impressed Reza with his faith in his instinct when advisers were warning him not to stir dislike with his campaign on crime and immigration. “I listen very little to people,” Mr Sarkozy confides. “They tell me to come over nice . . . I hate it when they tell me that kind of thing.”

Rude boy candidate

“You’re never happy, pauvre conne . . . A member of my family called Jacques has gone deaf. He has to have money for his hearing aid” rehearsing debate against Ségolène Royal.

“Who had this retarded idea? I don’t give a s**** about Bretons. I’m going to be surrounded by ten c***** looking at a map” on radar centre appearance in Brittany

“I don’t want to be followed by these c***** who I never see. What kind of a picture is that, a guy arriving surrounded by an army of bloody stupid publicists?” complaining about publicity staff

Explore World News

• World Agenda

• Iraq News

• US & Americas News

• Europe News

• Middle East News

• Afghanistan News

• Asia News

• Africa News

• Ireland News

Times Recommends

• Plan for 9/11 trial in New York divides the city
• Beijing gets the jitters as Obama flies in
• Potshot Palin settles scores