Shyama Perera: Of course the poor woman couldn't survive on £20 million

A second home in London is a must-have. Next, is a new body

Insurance magnate John Charman's claim that his wife should have accepted a paltry £20m divorce settlement is enough to bring any right-thinking woman out in hives.

He pronounces that the sum "should be impossible for any reasonable person to spend in their lifetime". So, what does it matter that she has actually been awarded £48m? He still has £80m, or four lifetimes, to himself.

But the feminist take on division of spoils is not the issue here. What is interesting is the cost of living for the über-rich.

Mrs Charman is a woman scorned. She has been ignominiously dumped at the moment when the menopause is playing mean tricks with midriff bulge, low sex drive and hot flushes.

Reinvention is necessary, not just to rebuild her self-esteem, but to help her embrace life positively. Trapped, as she is, in the stockbroker belt - Sevenoaks, a hamlet filled with comfortable, self-serving, very English, very married, well-to-do middle-classes - escape is inevitable.

A second home in London is a must-have. How much will that set her back? Well, Mick Jagger, a man not celebrated for largesse, recently forked out £6m on a Chelsea house. Big bucks, then.

With the move comes the make-over. Restoring Mrs Charman's body to its former glory at a time when all points will be moving determinedly south, will be difficult and costly.

Private health clubs in the area will charge up to £5,000 a year, and she will need a personal trainer three times a week. Vanessa Feltz fell for hers, and that may have eased the bills, but it is the default scenario.

Then there is the tan. Mrs C will surely achieve hers by booking suites in the sun at £4,000 a night, and enjoying the white sands of Barbados and Phuket.

She will trade the black work suits and the floaty skirts and pretty cardigans of the countrified rich, for designer frocks that nip and tuck and, hopefully, make her ex-husband review his departure with some regret.

Does she need couture? Of course not. But why should any woman who can afford £2,000 dresses and £800 shoes compromise? The whole point of having money, is that you do not have to? And there is the rub.

By 2007, then, Mrs C will be svelte and glamorous and living a double life - part city socialite, part country mother. Her hair, at present in need of colour, style and condition control, will be in the sort of hands for which our Prime Minister's wife happily pays £250 a day when the schedule is tight.

Ready to take on the world, the next wise investment is a youthful trophy lover. He may not have her ex-husband's skills at risk-management, but he'll be well-endowed elsewhere.

Simple candlelit dinners for two, costing up to £500 a time at Gordon Ramsay or Sketch, will be the prelude to energetic nights of bliss that she has long forgotten are possible.

It is small bananas for the pay-off, as a number of old men with young models on their arms, will testify. Let us wait and see what Mr Charman turns up with, before judging his wife, should she take this route.

Now for the final touch. The latest demographic is that women over 50 are increasingly investing in convertible sports cars. Mrs C can afford the sublime: an Aston Martin DB9 for £120,000. For more serious stuff, such as attending her duties as a magistrate, she'd be wise to find something a bit less flashy: a Bentley Azure, perhaps, at £260,000.

So here we are, less than a year into the divorce a good £8m has already been accounted for. That is not including day-to-day expenses. As Mrs Charman's lifestyle changes, she will need more not less. £20m? It's a joke.