I assure you I don’t normally consult books on etiquette but I wouldn’t expect you to believe me. After all no one admits to possessing such a guide, and yet bookshops shift thousands of the things annually so a lot of people must be keeping quiet about the fact that they can tell you exactly how one sets place cards for members of the royal family or what to wear at the state opening of Parliament.

The new Debrett is full of invaluable advice about how one politely joins an Internet discussion group, how it is unforgivable to end a relationship by fax and that it’s now acceptable (given the lamentable increase in gate-crashing of late) to print “Please bring this invitation with you” when inviting someone to a party. The jury is still out on bouncers (correct form of address).

Personally, I am all for rule books. They give us the choice whether or not to abide. My problem with Britain is all the unwritten rules (nowhere is it stated, for instance, that the sovereign is obliged to invite the leader of a winning party to become Prime Minister).

But, on tipping, Debrett continues to defend the absurdity of our status quo. While it is expected that we pay 10 per cent over the going rate when dealing with hairdressers, cabin stewards and waiters, we don’t tip hair stylists, air stewards or waiters at another man’s club.

Why? Debrett doesn’t tell us, presumably because the answer does our society no credit. The British tip not to reward exemplary service but because certain people are woefully underpaid.

If we tipped on the basis of a job well done you’d see parents at the school gate with envelopes of money every time the GCSE results are published, and I would have slipped the doctor a quid for coming out to Tom on

Saturday night.

No, we dole out tips to the underpaid because it is cheaper than paying them a decent wage. It is iniquitous and condescending and if Debrett ever wants to be treated like a textbook it’s going to have to start offering explanations as well as rules.