The Social Issues Research Centre (could they sound any more British?) brings us this handy and insightufl guide to British pub ettiquette:
Donít ever introduce yourself. The ďHi, Iím Chuck from AlabamaĒ approach does not go down well in British pubs. Natives will cringe and squirm with embarrassment at such brashness. If your introduction is accompanied by a beaming smile and outstretched hand, they will probably find an excuse to get away from you as quickly as possible. Sorry, but thatís how it is. The British quite frankly do not want to know your name, or shake your hand Ė or at least not until a proper degree of mutual interest has been well established (like maybe when you marry their daughter).
All very accurate. In my brief survey, I couldn't find a section on gratuities. Generally speaking, you don't tip anybody in a British (or Irish) pub. I speak from experience when I say if you leave your money on the bar, they'll hand it back to you. For the North Americans, there's also an important section on round-buying.