Katherine Butler: To live, and die, for the thrill of speed

Was it, I wonder, an evening at the cinema that brought Stirling Moss to his senses? The veteran racing driver announced his retirement yesterday, admitting that he felt terrified on his last outing in Le Mans. But were the seeds for this rather delayed realisation (at age 81)– that driving around a circuit in a metal box at inhuman speed can be lethal – sown as he watched Senna, the new documentary about Formula One's best loved and most tragic figure?

Seeing Senna at the weekend certainly corrected my perception of the sport. Where I was wrong was in thinking it is tedium embodied. Extraordinary on-board footage from Ayrton Senna's last competition, the 1994 San Marino Grand Prix, let me understand for the first time (modern on-board filming is less vivid, apparently) how intoxicating it must be to drive at speeds of 220mph. And, how violent your death will be if you crash. I also left the cinema more convinced than ever that Formula One is a hideously corrupt, greedy, and deeply sinister business.

The makers of Senna did not set out to paint an ugly portrait of a sport they clearly love. They wanted to understand the man, rather than investigating his death at 34, a waste of talent so shocking in his native Brazil that the country went into three days of national mourning. "It was just bad, bad luck and that's the story we tell," Manish Pandey, the film's writer, has explained. But they could hardly avoid Jean-Marie Balestre, the Frenchman who was then head of the Federation Internationale de l'Automobile (FIA), and who, it seems, was straight from central casting for men who run the governing bodies of world sport; a certain age, grey hair, manipulative, bullying and with a very flimsy grasp of the meaning of democracy.

"The best decision is MY decision", Balestre bellows as Senna leads a mutiny of drivers demanding a rule change to improve safety in one of the many segments of compelling contemporary footage in the film. Balestre's friendship with the French driver Alain Prost, Senna's arch-rival, the film implies, contributed to all kinds of skulduggery. It was every bit as repellent, in fact, as the latest Formula One charade over whether the Bahrain grand prix would go ahead, even as staff at the track in the Gulf autocracy were being arrested for being the wrong religion.

The film's power is in seeing Senna, a magnetic figure with a near-mystical belief in the fair play that should underpin true competition, come to realise how vile the money-driven "politics" practised by the sport's rulers really are. And with that come nerves. By Imola in 1994, the once-fearless charioteer looks nauseous as he contemplates the fatal track you, the spectator, know will kill him. Another telling moment comes when Senna is asked which driver has given him the greatest satisfaction to compete against. Terry Fullerton, the Brazilian replies. Fullerton was a youth Go Karting champion from London, whom Senna competed against as a teenager in the 1970s. "It was pure driving, there wasn't any politics, no money involved either, it was real racing," Senna says ruefully.

A sport in which greedy old men send young athletes out to race at suicidal speeds for massive commercial gain, and which depends on the patronage of oil-rich Arab tyrants, was never going to have much of a moral compass about human rights in Bahrain. So now that Senna's memory is safely preserved on film, and Stirling Moss has walked away from his petrol-head days, perhaps it would be fitting if the sport's governance relocated permanently to that awful little island in the Gulf.

Who will reveal the married couples' code?

Lily Allen's wedding seems to have been a happy event on Saturday. Less flamboyant but possibly even more joyful scenes took place at a small engagement party I attended the same day. The prospective groom will not, I'm sure, object if I point out that he is no Lily Allen, in age or personality. Nor will he mind me observing that friends were astonished and delighted when this never-married-before gentleman suddenly announced he had met The One. But he used his engagement speech for a tongue-in-cheek lament about how he and his intended might have begun their romance years before. If only.

In several cities over many years, he explained, they had lived almost cheek by jowl and, for heaven's sake, had mutual friends. But the two serious singletons, neither the type to go clubbing or speed dating, remained solitary and oblivious to one another's existence, because the mutual friends never thought to introduce them. I hope the speech struck a chord with couples present, because I have often wondered if there is a conspiracy among the happily married never to introduce single friends to each other. Is it an unwritten rule in the Couples' Code? I am now relying on Andrew and Elizabeth to find out.

Old, new or comfortable. Wear what you want, Kate

You know how it is. You've accepted an invitation but you've nothing to wear. So you root in the back of the wardrobe and find ye olde blue outfitte. The cut is a bit dated, but hey, nobody will remember they saw it before. That was probably not the scenario that preceded Kate Middleton's carefully orchestrated decision to trot out something she'd worn four years ago to an official engagement last weekend. "Duchess of Thrift" may even have been the headline that royal spinners, anxious to make sure the Princess Ordinary idea doesn't die, were hoping for.

But anyone reading about "royal recycling" would think she'd gone out in a sturdy tweed skirt and a scarf knotted under her chin like the Queen at Balmoral. Wearing something twice, is that really such an economy? Then again, she can't really win, so, like the Slut Walk girls, she might as well wear just whatever she wants.