You're coming to England on holiday? Great? You've got the airline tickets, hotel vouchers, traveler's checks and passport? You've packe dyour raincoat, galoshes and collapsible umbrella?

Just one more thing: You'll need a copy of the English Tourist Board's "Twenty Tips for Visitors." If you travel agency hasn't supplied it, we'll be happy to provide one free-of-charge when you land at Heathrow.The growth of mass tourism--by between 30 percent and 45 percent in many historic towns since 1983--has provoked a backlash from irascible residents. The code of practice is a somewhat graceless attempt to cool tempers.

The purpose of publishing it, says the board, is "improving the relationship between visitors and the residents of the areas they go to see and enjoy...Our aim is to make a positive contribution to the essential task of ensuring that the future is one of harmony, not of conflict."

The code smacks of the list of Do's-and-Don'ts the U.S. Army dished out to British-based GIs during World War II on how to treat the natives--except that it is less tactfully worded. It appears to have been compiled by a committee of misanthropic insomniacs, museum curators and park wardens.

"Keep noise-levels down," says the code severely, "especially at night. Don't carve your initials on trees and historic monuments or spoil them with graffiti. Leave beaches, parks, and public places as you would like to find them. Don't argue with staff who seek to enforce rules. Keep an eye on your children to see they don't indulge in destructive or annoying behavior. If you want to photograph other people, ask them first, Don't push, shove or jump queues. Good manners are always appreciated: don't forget to say please and thank you."

The code is well-meaning but mendacious. It seeks to give the impression that Britain out-of-season is a quiet, reticent, courteous, orderly society, innocent of the clamorous spirit of sel-assertiveness that has overtaken Western civilization everywhere else since the 1970s.

British people who have read it are amazed at the fantasy of British life it projects. For heaven's sakes, where has the English Tourist Board been?

In the interests of international understanding, a public-spirited group of Londoners is preparing an amended code for tourists. It's still on draft form, but here are some extracts:

--If you're under 20, always carry a three-foot-long boom box turned up fortissimo, especially on the street at night. Keeping noise-levels down will ruin you socially with your peer group.

--Lord Byron (an English tourist) carved his initials on the Temple of Poseidon at Sounion, outside Athens. Why should you feel inhibited? Many London walls are covered with graffiti, and as a visitor you will be expected to make your creative contribution.

--The British, with characteristic enterprise, have assembled the world's largest collection of non-biodegradable solft-drink bottles and hamburger cartons, which they have placed on their beaches as site-specific abstract art installations. Please support this imaginative cultural project.

--It's tue: Protesting to hotel and restaurant staff about ridiculous rules is a waste of time. A substantial bribe is far more effective.

--It has been said that the British are the only race on earth who don't much care for children. This is a monstrous falsehood. They respect children--and use them constantly in crowded places like the Tower of London, Madame Tussaud's and the London Underground (see below as assault troops armed with iced lollies, molten chocolate and leaking fruit-juice containers. You have every right to employr your own offspring in the same manner.

--These days, if you accost a pretty girl in the street and tell her you wish to photograph her she will probably have you arrested. Stick to Nelson's Column and the Houses of Parliament.

--Unless you push and shove, you will never get on to a Tube train in the rush-hour. The correct method is to grab the shoulders of the two little old ladies standing immediately in front of you on the platform, prise them firmly apart, squeeze your body forward until you can reach one of the overhead straps inside the carriage, and then lever yourself in, complaining bitterly that you are being unreasonably ubstructed. Always carry health insurance in case of broken limbs.

That's the provisional list. As we say in the tourist