'I'm not saying I'm Jesus. That's for other people to say' – Stewart Lee

The big debate in the country at the moment revolves around the actions and opinions of a power-crazed Roman Catholic. I'm talking, of course, about Tony Blair. On the occasion when Popcorn Double Feature met Blair – imagine When Harry Met Sally without the sexual tension – he certainly gave the impression of being someone who thought of himself as God's gift (just for the record, I never met Bill Clinton, although I did dine at a table next to Monica Lewinsky's. Close, but no cigar).

Smug, conceited, arrogant, yet utterly charming, you couldn't make Blair up. And you wouldn't want to. But in The Special Relationship, writer Peter Morgan finds himself irresistibly drawn to his factional version of Blair for the third time after The Deal and The Queen. Morgan's clearly fascinated by the man's mercurial personality and he's described his Blair Triptych Project as charting the creation of a 'monster'. The Blair at the beginning of The Special Relationship isn't yet a monster, but by its conclusion you definitely wouldn't go into the woods with him.

The Special Relationship focuses on what happened when Blair met Clinton. Imagine When Harry Met Harry with the sexual tension. Michael Sheen – now so comfortable as Blair that he almost is him, rather than an actor playing a part – brilliantly captures his character's wide-eyed delight at the US leader's political superstar status. If Blair is the epitome of gauche ambition, Clinton is like a cool older brother who's totally comfortable in his head honcho skin.

The film has been described as a 'bromance' and that's inescapably the case. Cole Porter's Friendship plays over the opening credits ('If you're ever in a jam/Here I am/If you ever need a pal/I'm your gal') and some scenes of male bonding would slip unnoticed into Paul Rudd and Jason Segel's I Love You, Man. However, Morgan's clever script also hints at Blair's magpie nature and his desire to match Clinton's global standing. The young British PM, excited and stimulated by the older man's presidential presence, looks at him and thinks: 'I'll have what he's having.'

None of this would work without Dennis Quaid's tremendous performance as Clinton. Quaid has described America's 42nd President as 'a cross between an intellectual giant and a good ol' boy from Arkansas' and someone who 'intensely wants to be liked'. And, indeed, it's impossible not to like him – and therefore to understand why Blair likes him, too.

Yet as the story unfolds, the underlying tragedy of their relationship – or at least, Morgan's take on it – is revealed. Quaid's Clinton, his own reputation tarnished by his affair with 'that woman', can see the seeds of destruction cultivating in the fertile hothouse of Blair's ambitious personality. There's a new political buddy coming over the horizon and he's mad, bad and dangerous to know. As one of Blair's forebears Harold Macmillan said in 1957, the Prime Minister will eventually realise he 'never had it so good' with Bill and hanging out with George W will blight his legacy for ever.

'Men and women can't be friends' – Harry Burns (When Harry Met Sally). That isn't true, but maybe it is the case with world leaders.

The Special Relationship (Optimum Home Entertainment) is released on Blu-ray and DVD on 20 September.

Colin Houlson