George Osborne is finding out that hell hath no fury like a host scorned

This is the Establishment at work. The first rule of any house party is that guests don't spill the beans. And you certainly don't rock the boat, or superyacht in this case, if you have been entertained aboard.

Hell hath no fury like a host scorned, as AN Wilson once found to his cost. Lord Wyatt accused Wilson of "the grossest impropriety" for disclosing, in 1990, minor details of a dinner-party conversation with the Queen Mother in a Spectator article ("I can't understand a word Prince Michael says," said the Queen Mum. "He will mumble into his beard"). As the host, Wyatt felt mortified by this breach of etiquette. Convention insists that conversations with a member of the royal family should never be repeated.

Even Max Mosley expected the prostitutes to obey similar "house rules" at his S&M orgy and maintain their discretion. His private party alas ended up in the News of the World.

But the ultimate house party where such rules went awry took place, of course, at Cliveden, the family home of the Astors, in 1961, when John Profumo had a chance meeting with showgirl Christine Keeler, who was cavorting in the swimming pool.

Within months rumours had leaked out about their affair and despite Profumo's protestations to the House of Commons that there was "no impropriety whatever", he later confessed he had misled the House and resigned. David Cameron is only too aware of such precedents - his stepfather-in-law is Viscount Astor.

The unofficial code of conduct is enshrined in the Chatham House rules, dating from 1927. Most people think that means you can't quote anything that is said at a gathering. In fact, the rule is more relaxed. According to Chatham House itself, "participants are free to use the information received but neither the identity nor the affiliation of the speakers may be revealed".

Osborne did not break the law, as far as we know, but he displayed an appalling lack of manners which in Establishment circles is just as bad. "I don't mind if you don't like my manners," said Humphrey Bogart in The Big Sleep. "I don't like 'em myself. They're pretty bad. I grieve over them on long winter evenings." Osborne will no doubt be grieving over his in the days to come.