Some odd people have been fantasising that Gordon Brown is Hugh Grant. Not the actual floppy-topped actor, but the fictional prime minister whom Grant portrayed in the atrocious film Love Actually.

The Bushwhacking lobby drooled as Grant’s PM used a press conference to tell off the US President for turning the special relationship into “a bad relationship”, and vowed that “the country of Shakespeare, Churchill, the Beatles, Sean Connery, Harry Potter, and David Beckham’s right foot” would stand up to the American “bully”. They have dreamt since of Mr Brown doing a Hugh. But what happens when Mr Brown goes to Washington? He announces that America remains Britain’s key ally, with a “shared destiny”, and expresses his gratitude to the Bush Administration.

It is time my old friends on the Left stopped deluding themselves. Chancellor Brown backed the Iraq war in 2003, albeit silently, and Prime Minister Brown would have backed it publicly. Here are three reasons why.

First, that is what Labour leaders do. The MP who accused Tony Blair of spoiling Labour’s “tradition of anticolonialism” can’t have been thinking of the party that built the British bomb and led colonial wars in the Forties; backed the Vietnam War and sent troops into Northern Ireland in the Sixties; supported the Falklands Task Force in the Eighties; and bombed Iraq and Serbia in the Nineties.

Secondly, as Mr Brown implies, Britain’s standing as a power in the world relies upon the US alliance. That was ultimately why Mr Blair supported the invasion of Iraq, and why Mr Brown (or David Cameron) would have done the same. It wasn’t love, actually, but realpolitik. The alternative, as a Royal Navy chief recently put it, would be to accept that we are a middling nation “like Belgium”. Beer lovers may not mind that, but it would hardly be to the taste of a power-thirsty, puritan Prime Minister.

Thirdly, Mr Brown is at least as keen as Mr Blair on strutting about the world to give his Government a sense of mission. He was behind the “ethical foreign policy” that led to Iraq via Kosovo, has declared a “moral crusade” in Africa, and plans further intervention in Darfur.

No doubt Mr Brown would like to keep President Bush at arm’s length, extricate British troops from the Iraqi mess (who wouldn't?) and prefers “soft power” bullying to war. He even used MPs’ discontent over Iraq in his backstage plot against Mr Blair. But don’t be fooled into thinking he could ever follow the Love Actually script on the public stage. Despite the fantasies of the “Hugh Brown” groupies, he was as likely to scold the President over Iraq as to emulate Grant’s PM by getting off with the lady who serves his tea in No 10.

Times Recommends

• Navigating the new global archipelago
• Comment: McCain isn't Bush and voters know it
• Religion's history of self-inflicted pain