Sarah Sands: As the Gibbs well know, there is no such thing as a free holiday

It is insidiously corrupting to have friends richer than you

There is no such thing as a free holiday. Tony Blair has suffered ridicule, calamitous loss of dignity and happy hordes of paparazzi. All for a not-even-that-hot holiday in a not-so-nice house surrounded by grotesque all-u-can-eat restaurants. Tonight, his hosts Robin and Dwina Gibb may pitch up with all their druid lesbian friends, acquired through a long and open marriage.

The Blairs are accused of grabbing a free holiday, but they have actually paid a very high price. There is the sanctimonious din from the Tory party, including Philip Davies's accusation that Mr Blair "has been caught with his trousers down", a disturbing metaphor given the sexual boasts of his hosts. Worse, the Blairs are now bound to the Gibbs for better or, more likely, for worse.

I would have thought that the £40,000 or so in lost rent (let's just put aside Downing Street's economical claims that Mr Blair has made an unspecified payment) was a smart investment for the Gibbs. For all our cynicism about politicians, a visit by the Prime Minister still counts for something. British soldiers injured in Iraq and Afghanistan would certainly appreciate one.

American patriots will pay more to rent the Gibbs' villa, knowing that Mr Blair was the last person in the bathroom. Of course Dwina Gibb was anxious to claim that the Blairs were not paying for their holiday. A commercial transaction would downgrade their relationship. Instead, she told the Daily Mail, dewy with intimacy: "Robin's friendship with Tony has nothing to do with politics - it is pure friendship. You know, Tony has always been interested in music and is a great fan of Cliff and the Bee Gees too, and he's a great friend."

The Prime Minister had already paid his debt in full before he arrived. At a Labour rally in 2005 he said: "I was completely star-struck tonight. I met one of my heroes - Robin Gibb."

Mr Blair's capacity to be star-struck by power, fame and money has been an idiosyncrasy of his premiership. Politics is a form of show business for him. He was always at his best before audiences and if he could have played the Labour conference live at the Super Bowl, he would have done.

His peevish observation that many of his university contemporaries seemed to be richer than he was came from the heart, and the wealth gap eats up Cherie. It is insidiously corrupting to have friends who are richer than you are. Either you bluff your way, in the manner of Conrad and Barbara Black and risk jail, or you accept your role as supplicant. Guests of the rich laugh very loudly at their hosts' jokes and find their opinions extraordinarily fascinating. If Robin Gibb gets round to discussing geopolitics with the Prime Minister he will be listened to as if he were Henry Kissinger.

Holidays are the point at which the most prune-faced puritan will crack. It is such a proportionately huge sum for everyone, even for the comfortably off. What harm can it do? Well, for the Prime Minister, it is loss of reputation. For Diana, Princess of Wales, a free holiday with the al-Fayeds meant the loss of her life.

In other circumstances, the dilemma is more exquisite. What would you do if the genial Hong Kong businessman and aesthete David Tang invited you to his New Year party in Phuket? The Duchess of York and her daughters were certainly not going to be put off by the fact that Kate "cocaine" Moss was a fellow guest. Only the psychologically flawed, the workaholic and the wholly honourable could resist the temptation of a free holiday. Tony Blair's weakness is Gordon Brown's strength.