Is it legal for a UK bar to refuse to accept 5p in copper coins as part payment for a drink?
No it is not legal to refuse 5p in copper coins - there must have been a reason! Are you sure the coins were British and not euro coins? Did you ask them why they would not take your money? It seems very strange to me.
money is legal tender, so there should be no legal reason for them not to accept your payment (however much small change you use) they might not want to.
