This is a widely misunderstood and at the same time overanalysed concept, that of reasonable force? The thing is violence and aggression can manifest themselves in so many different ways the variables are infinite. So my task here is to provide a brief, simple explanation of reasonable force. The best way to get to understand the concept of reasonable force is by playing around with scenarios and situations in training because you, your shape, fitness levels, age, size are also part of the variables as the same things also affect how an attacker will be assessed as a threat too. hence my brevity here.

We, ordinary law abiding folk not criminals or predators, are constrained in our use of force by Section 3 Paragraph 1 of the Criminal Law Act 1967 which states under the section on use of force in making arrest, etc.

(1)A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large.

As this covers all circumstances including prevention of assault on ourselves or our loved ones, lets keep it to self defence, it is pretty wide ranging in its permission to use force, or so it seems until we consider the meaning of ‘reasonable’. Here people have gone on to write huge tomes on the subject and rightly so as it is a minefield, or can be legaly speaking. The thing is it is what is reasonable to you in the circumstances you find yourself.

The old fashioned standard that would be applied would be would the amount and type of force be reasonable based on the level of threat faced and the circumstances that threat was faced in by the ‘Man on the Clapham Omnibus’.  This would include the use of force before the crime (assault upon ourselves) was committed, perfectly acceptable under the correct conditions and circumstances.

Defence of ourselves is enshrined in law under this act, it should not be misused but errors in judgement when facing danger may occur, this is where a deeper understanding will help for sure. That is where our training comes in, years of experience can be shared in hours and theory and practice pulled together in order to assist an accelerated understanding.

Rembember before physical intervention and use of force comes avoidence, de-escalation, escape, deflection and deception. Use of force is only acceptable where the others have failed or it has not been possible to employ those strategies.  So explore the following pages on our website and seriously consider taking up our training BEFORE you regret you did not.

However, here is specific advice for homeowners facing an intruder from the Crown Prosecution Service.

Householders and the use of force against intruders

Joint Public Statement from the Crown Prosecution Service and the Association of Chief Police Officers

What is the purpose of this statement?

It is a rare and frightening prospect to be confronted by an intruder in your own home. The Crown Prosecution Service (CPS) and Chief Constables are responding to public concern over the support offered by the law and confusion about householders defending themselves. We want a criminal justice system that reaches fair decisions, has the confidence of law-abiding citizens and encourages them actively to support the police and prosecutors in the fight against crime.

Wherever possible you should call the police. The following summarises the position when you are faced with an intruder in your home, and provides a brief overview of how the police and CPS will deal with any such events.

Does the law protect me? What is ‘reasonable force’?

Anyone can use reasonable force to protect themselves or others, or to carry out an arrest or to prevent crime. You are not expected to make fine judgements over the level of force you use in the heat of the moment. So long as you only do what you honestly and instinctively believe is necessary in the heat of the moment, that would be the strongest evidence of you acting lawfully and in self-defence. This is still the case if you use something to hand as a weapon.

As a general rule, the more extreme the circumstances and the fear felt, the more force you can lawfully use in self-defence.

What amounts to disproportionate force? I’ve heard I can use that.

The force you use must always be reasonable in the circumstances as you believe them to be. Where you are defending yourself or others from intruders in your home, it might still be reasonable in the circumstances for you to use a degree of force that is subsequently considered to be disproportionate, perhaps if you are acting in extreme circumstances in the heat of the moment and don’t have a chance to think about exactly how much force would be necessary to repel the intruder: it might seem reasonable to you at the time but, with hindsight, your actions may seem disproportionate. The law will give you the benefit of the doubt in these circumstances.

This only applies if you were acting in self-defence or to protect others in your home and the force you used was disproportionate – disproportionate force to protect property is still unlawful.

I’ve heard that I can’t use grossly disproportionate force. What does that mean?

If your action was ‘over the top’ or a calculated action of revenge or retribution, for example, this might amount to grossly disproportionate force for which the law does not protect you. If, for example, you had knocked an intruder unconscious and then went on to kick and punch them repeatedly, such an action would be more likely to be considered grossly disproportionate.

Do I have to wait to be attacked?

No, not if you are in your own home and in fear for yourself or others. In those circumstances the law does not require you to wait to be attacked before using defensive force yourself.

What if the intruder dies?

If you have acted in reasonable self-defence, as described above, and the intruder dies you will still have acted lawfully. Indeed, there are several such cases where the householder has not been prosecuted. However, if, for example:

  • having knocked someone unconscious, you then decided to further hurt or kill them to punish them; or
  • you knew of an intended intruder and set a trap to hurt or to kill them rather than involve the police,

you would be acting with very excessive and gratuitous force and could be prosecuted.

What if I chase them as they run off?

This situation is different as you are no longer acting in self-defence and so the same degree of force may not be reasonable. However, you are still allowed to use reasonable force to recover your property and make a citizen’s arrest. You should consider your own safety and, for example, whether the police have been called. A rugby tackle or a single blow would probably be reasonable. Acting out of malice and revenge with the intent of inflicting punishment through injury or death would not.

Will you believe the intruder rather than me?

The police weigh all the facts when investigating an incident. This includes the fact that the intruder caused the situation to arise in the first place. We hope that everyone understands that the police have a duty to investigate incidents involving a death or injury. Things are not always as they seem. On occasions people pretend a burglary has taken place to cover up other crimes such as a fight between drug dealers.

How would the police and CPS handle the investigation and treat me?

In considering these cases Chief Constables and the Director of Public Prosecutions (Head of the CPS) are determined that they must be investigated and reviewed as swiftly and as sympathetically as possible. In some cases, for instance where the facts are very clear, or where less serious injuries are involved, the investigation will be concluded very quickly, without any need for arrest. In more complicated cases, such as where a death or serious injury occurs, more detailed enquiries will be necessary. The police may need to conduct a forensic examination and/or obtain your account of events.

To ensure such cases are dealt with as swiftly and sympathetically as possible, the police and CPS will take special measures namely:

  • An experienced investigator will oversee the case; and
  • If it goes as far as CPS considering the evidence, the case will be prioritised to ensure a senior lawyer makes a quick decision.

It is a fact that very few householders have ever been prosecuted for actions resulting from the use of force against intruders.


Reasonable Force

However, the most common question I get is, surprisingly, if I use self defence and the person attacking me dies what happens?

Well its a world of hurt for you to to be honest. Did not expect that answer? Well the truth is really useful and offered by us even if it is difficult to digest.

The thing is the law allows for the use of reasonable force for the prevention of crime, getting that right and articulating it after an attack is all important.

Here is a little article from an expert and friend of mine;

On Using Lethal Force- Marc MacYoung


I often tell people “Self-defense is a small target in a big landscape of violence. It’s very easy to miss and missing has consequences” When it comes to use of lethal force that target gets way, way smaller. And the consequences become, much, much harsher.

In many ways we make a serious mistake when we separate moral, psychological, emotional, legal, social and faith issues when approaching this subject. Primarily because we tend to try and judge it from only one of those perspectives. Not only does one perspective gives us the wrong answer, but when we’ve chosen one as ‘most’ important we often dismiss other perspectives as unimportant. While on the internet we can argue our position in comfort, safety and self-righteousness, in reality, these ignored positions will rise up and bite us in the ass. Namely because that which we deemed, unimportant, just proved itself important and you’re unprepared.

But in another important consideration, we do have to separate these unique considerations and understand them individually. We have to do that before we can recombine them. This in order to assess the whole of the issue and how they influence it.

If your moral, ethical and faith standards are that killing is categorically wrong, then you’re going to have serious psychological issues if you choose to abandon those standards in order to live. Or you can choose to follow them and — if you’re lucky — die. (If you live you’re going to have to live with injury, crippling and trauma of not acting.)

Still, if your personal ideology allows for taking a human life to protect yours and others, then you’re still going to have to live with the aftermath of doing so. Not only have you violated one of the biggest social prohibitions, but there will be legal consequences (This is of course assuming you don’t know how to successfully dispose of a body.) This is not only going to put strain on you, but also your loved ones and the family finances.

All of this ignores the very real issue that most people overlook. That is let’s say that you allow that taking another human life in self-defense is justifiable. Well that’s just fine and dandy except for one thing. The biggest problem about using lethal force in self-defense is the conditions that you allow that it is justifiable just happen to contain that someone is actively trying to kill you. Believe me when I tell you this creates a whole new set of complications after you’ve worked your way through those other issues.”


For an in depth exploration of the law and self defence I suggest Marc’s latest book, ‘In the Name of Self Defence: When it’s worth it,  what it costs’. Whilst based on the law in the USA it is very easy to translate for our legal system.