I'm a strong advocate of "the fence" as promoted by Geoff Thompson. Keep you hands up and use them to maintain distance between you and your adversary. Don't wait for an attack - always strike pre-emptively and make sure you follow up your attack. Do not make the mistake of stepping back to assess the damage after a pre-emptive strike - if he is still standing then he is still a risk. I have seen many people strike pre-emptively only to then go on and lose a fight simply because they failed to follow up their attack after realising their assailant was unperturbed. Simply do what is necessary to escape and worry about the legal ramifications of the altercation later. (9 times out of 10 you can disappear before the police turn up in any event and, as long as you have't seriously injured the other person, these matters are rarely taken any further) This may sound a little over the top to some, but you cannot afford to take chances when it comes to self protection / self preservation. You never know how an alteracation will end and its better to "over-react" in one sense, than become a statistic