Amazingly for the British, who love queues, there is no formal line-up----the bar staff are skilled at knowing whose turn it is. You are permitted to try to attract attention, but there are rules about how to do this. Do not call out tap coins on the counter, snap your finger or wave like a drowning swimmer. Do not scowl or sigh or roll your eyes. And whatever you do, do not ring the bell hanging behind the counter---this is used by the landlord to signal closing time. The key thing is to catch the bar worker's eyes. You could also hold an empty glass or some money, but do not wave them about. Do adopt an expectant, hopeful, even slightly anxious facial expression. If you 1ook too contented and complacent, the bar staff may assume you are already being served.