Tim Walker: Make us laugh, Sean, and we'll forgive you

It's the Oscars next week: one final awards season flurry of frocks and fawning. It being their best opportunity to deliver a speech they wrote themselves, we ought to brace ourselves for a few more actors' man-in-the-pub political views, too.

Some Hollywood liberals are rather good at this: George Clooney used his acceptance speech at the Golden Globes to thank Brad Pitt for his humanitarian activities, then dispelled all awkwardness with a joke about Michael Fassbender's penis.

Some are less so: like a latter-day Hanoi Jane atop the metaphorical Argentinian gun battery, Sean Penn has been wittering cluelessly about the Falklands. This, of course, angered anyone on the right-hand side of the British political spectrum. But Penn's great achievement was to wind up everybody else as well.

I'm convinced this has less to do with his moustache than with his apparent lack of any sense of humour whatsoever. When Chris Rock cracked a couple of jokes about Jude Law at the 2005 Academy Awards, Penn took it upon himself to inform the audience, in all earnestness, that Law was "one of our finest actors". Everyone duly cringed.

This week, the National Archives released an MI5 file on Charlie Chaplin, revealing how keen the US authorities were to get rid of a man J Edgar Hoover privately described as one of "Hollywood's parlor Bolsheviks".

Chaplin was hounded from the US for his progressive views in 1952. Twenty years later, though, he returned in triumph to collect an honorary Oscar. Present an award this year, Sean, tell a witty joke about your South American sojourn, and you still have a shot at a Lifetime Achievement Bafta, circa 2032.