I know that life is a lot easier when you are worth £800m, but I do feel sorry for Paul McCartney following the announcement that his second marriage to Heather Mills, 20 years his junior, is officially over.

But Paul married a person, not a placard, and over the last few months there have been few more embarrassing sights than that of Fab Macca being touted around the world protesting in front of the world's cameras about everything in a fur coat, from seals to dogs to cats.

Heather Mills made the classic mistake of thinking she was every bit as intelligent and interesting as her husband - and the fact is, she's not. Tenacious, yes, determined, certainly, but there was only one award-winning creative genius in that household, and it wasn't her. Throughout his career, Paul McCartney has donated millions of pounds to charity, mostly anonymously. He has supported charities, schools and hospitals in Sussex, as well as global causes such as Aids and poverty. I've met him on numerous occasions and cannot think of a more self-effacing person.

Heather, on the other hand, clearly thought she had married upwards, forgetting perhaps, that Paul and Linda sent their children to state schools and took their holidays in a bothy in the west of Scotland. Paul travels around London on a scooter, wearing a crash helmet for anonymity. Heather wanted to launch herself as a crusading campaigner along Princess Diana lines, with Paul as her consort - big mistake.

Linda McCartney, pictured right, was a campaigner for animal rights too, and a passionate vegetarian, but Paul felt comfortable with those causes and he and Linda had a rock-solid marriage. Their children have been brought up to respect other people and have incredibly good manners. After Linda's death it was understandable that Paul would seek companionship, and that also any new relationship would be difficult to integrate into this tightly knit family grieving over their mother's death from cancer.

But in the end, it is better to live alone than with someone who just nags. And when Paul McCartney went on a hugely successful tour of America, I realised that his marriage was heading for the rocks - because that's a way of avoiding your wife. Stella and Mary will not be gloating that dad is on his own again - far from it - I suspect they will be supportive and understanding. I'm a bit younger than Paul at 59, and his songs have formed the background to so much of my teens and 20s. Like all super-successful creative people, he's self-centred and extremely touchy about ageing in a young person's business. But I can understand why he'll want to spend his 64th birthday next month surrounded by friends and supporters, not a moaning Minnie who's nagging him about landmines and his hair colour. He's earned the right to a paunch in peace.

* Jamie Oliver's campaign to improve school meals has led to a decline in numbers of children actually taking them, as parents opt for packed lunches until there is a discernable improvement in standards.

Prue Leith, the chairman of the British Food Trust, entered the fray with a speech this week calling for the elimination of choice in school food, as part of a drive to raise standards.

Opponents of this idea claim that children should not be denied choice "because it is a skill they need to learn for all areas of life". However, is it worth exercising a choice between reconstituted meat, fried fish and burgers? Surely it would be better to re-educate the nation's palates from scratch, starting with those children of primary school age?

New scientific research shows that food cravings and any resultant over-eating are caused by neurological patterns in the brain. Some people, it seems, are more sensitive to certain food "cues" than others, which might explain eating disorders such as bingeing and bulimia. You don't even have to shovel down a bar of choccie to trigger off a craving - pictures of food can induce exactly the same effect. In spite of this, we remain a nation who happily eats more muck than any other in the civilised world, with the exception of America.

I'm currently filming a television series with Gordon Ramsay, The F Word, for Channel 4, and trying to break down people's sheer ignorance about the merits of different foods.

It is completely obvious that most of the public can't cook, that they have no idea what to do with all these fancy ovens they insist on installing in their built-in kitchens, and are riddled with weird ideas about where food actually comes from. So expecting most parents to come up with meals packed with nutritious goodies each day is ludicrous.

The Government needs to fight obesity by funding school meals properly, making them compulsory and no-choice, coupled with lessons in nutrition and basic cooking techniques instead of "Britishness".

* Every time a new list of nominees is announced for the Turner Prize, it elicts a feeble knee-jerk reaction from an embittered group of artists known as the "Stuckists". Who cares what this completely and utterly irrelevant small coterie of self-publicists think? They seem to spend their time getting publicity by denouncing conceptual art as the devil's work. The Turner Prize and Becks Futures both entice thousands of young people into art galleries for the first time every year. They fulfil a valuable role and the Stuckists should put up or shut up. It's time they changed their tune.