“A defendant is entitled to use reasonable force to protect himself, others for whom he is responsible and his property. … It must be reasonable.” — Beckford v The Queen 
We are often asked by our members: "When can I use Krav Maga to defend myself, and how much Krav am I allowed to use when I do?". By Krav Maga, our members really mean use of force - which is any form of physical intervention, be it use of pushes, punches and kicks, joint locks and leverage or pain compliance, and so on.
This is a great question, but a great question without a directly straightforward answer - just like self defence law or indeed self defence itself. In fact, when we talk about self defence - we are actually talking about the law which is a point not many people know, including some practicing martial artists!
Please understand that self defence is therefore essentially a legal concept, not a system of techniques or fighting skills.
Generally speaking, when using force for self defence what we do must be reasonable and we must be able to justify our actions. You can't just groin shot somebody because they look at you sideways - if you do, you'll probably fall foul of the law...
So, what does UK law tell us?
Section 3(1) of the Criminal Law Act 1967 tells us that use of force is reasonable:
in the circumstances in preventing a crime or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large.
And to be reasonable - the use of force must be necessary and proportionate.
If we consider when use of force might be necessary, here are some examples taken from the Law Commission Draft Criminal Code:
To protect himself or another from unlawful force or unlawful personal harm - this is self defence broadened to cover defensive force in support of another person.
To prevent or terminate the unlawful detention of himself or another.
To protect property (whether belonging to himself or another) from unlawful appropriation destruction or damage.
To prevent or terminate a trespass to his person or property.
Effectively, proportionate use of force means (developed from case law):
the force used to repel a crime must be proportionate to the force threatened
what force is proportionate to the amount of harm likely to be suffered by the defendant
So what does this all mean for those of us training Krav Maga or another system?
Well, for example, if someone attacks us or another person, we are legally allowed to use force for self defence. The force we use MUST be reasonable in the circumstances - we need to have a good reason to be fighting with another person, and what we do back to the attacker MUST equal or thereabouts to the amount of harm we or another person is likely to suffer.
In other words - imagine that someone is strangling you. Obviously, using self defence skills here is reasonable - such as the Krav Maga choke releases - as this is an attempt on your life! It's absolutely necessary to use some kind of force to prevent yourself from being killed, so releasing yourself from the dangerous grab and then countering with strong strikes would seem proportionate to your potential death (the logical conclusion of being strangled).
Reasonable = Necessary + Proportionate.
But what else does the law tell us?
Well let's look at Section 76 of the Criminal Justice & Immigration Act 2008:
(3) The question whether the degree of force used by D was reasonable in the circumstances is to be decided by reference to the circumstances as D believed them to be.
(4) If D claims to have held a particular belief as regards the existence of any circumstances— (a) the reasonableness or otherwise of that belief is relevant to the question whether D genuinely held it; but (b) if it is determined that D did genuinely hold it, D is entitled to rely on it for the purposes of subsection (3), whether or not — (i) it was mistaken, or (ii) (if it was mistaken) the mistake was a reasonable one to have made.
(5A) In a householder case, the degree of force used by D is not to be regarded as having been reasonable in the circumstances as D believed them to be if it was grossly disproportionate in those circumstances
(7) In deciding the question mentioned in subsection (3) the following considerations are to be taken into account (so far as relevant in the circumstances of the case) — (a) that a person acting for a legitimate purpose may not be able to weigh to a nicety the exact measure of any necessary action; and (b) that evidence of a person's having only done what the person honestly and instinctively thought was necessary for a legitimate purpose constitutes strong evidence that only reasonable action was taken by that person for that purpose.
Section 76 of the Criminal Justice & Immigration Act 2008 tells us something very important - that we can act as we genuinely believe the situation to be, and that in the heat of the moment, we are not expected to weigh up exactly what or how much force is appropriate (within reason of course, you'll still need to be able to justify what you do or did later).
Violent confrontation is confusing and stressful, the law understands both this and that an individual's decision making might not be as clear as it would be in normal circumstances. Violence is brutal, fast and chaotic - it's not a physics calculation that you can work out in your own time!
Think back to the cheery scenario I mentioned above - where someone is strangling you. When you are fighting for oxygen while having your throat crushed, it would not exactly be fair to expect you to know or weigh up exactly how much force you must use to stay conscious and alive. As long as you would only do what you thought was necessary to survive, then you should be able to justify your actions as reasonable, if required to.
“If there has been an attack so that self defence is reasonably necessary, it will be recognised that a person defending himself cannot weigh to a nicety the exact measure of his defensive action. If the jury thought that that in a moment of unexpected anguish a person attacked had only done what he honestly and instinctively thought necessary, that would be the most potent evidence that only reasonable defensive action had been taken …” (Palmer v R 1971 AC 814)
Knowing that we can act according to how we genuinely believe the situation to be is another crucial detail, because it suggests we DO NOT have to be attacked first - that we can make the first move and use force to strike pre-emptively.
Being able to act first and use force pre-emptively might mean the difference between success and failure when defending ourselves from harm. If we have a genuine and reasonable belief that an individual is about to harm us and we have no time to avoid or de-escalate, then we may have grounds to use force.
Again, think of the strangulation scenario. What if the attacker had threatened to "fucking throttle you!" in a fit of snarling rage, during a heated exchange that you couldn't immediately escape from, before bursting towards you? If you had an honestly held belief that an attack was imminent - based on the seriousness of the threat - you could have grounds to act first and strike pre-emptively.
If we were to act too late - it might be too late!
Bear in mind it only takes a few seconds with minimal pressure to the throat be throttled to death...
"There is no rule in law to say that a person must wait to be struck first before they may defend themselves" (R v Deana, 2 Cr App R 75)
But for pre-emptive action, we need consider the Colour Code and our state of mental readiness.
We would need to be in Yellow to get to Orange, and we would need to be firmly in Orange to even consider using Krav Maga pre-emptively. This is why it's so important to understand the necessity to cultivate the correct mindset when it comes to self defence!
Absolutely, the more switched on we are - in Yellow - the higher chance we will have to avoid or de-escalate trouble in the first place, reducing the risk of harm to ourselves and of course potential involvement with the police.