The Use of “Reasonable Force”: A Guide for Security Professionals

With society and indeed the interactions we experience on a daily basis becoming increasingly violent and hostile, we asked the experts, our friends at to examining the uses and definitions of ‘reasonable force’. They will ask – and hopefully answer – such questions as, exactly how much force is considered reasonable? Why is it important to understand this? When does reasonable force become excessive force – and what alternatives could there be to using any kind of force at all?

Yes, it’s a tricky subject. It’s also notoriously difficult to blanket multiple scenarios involving countless variables with a single definition of what constitutes the ‘right’ and ‘wrong’ ways to act. This is why the law attempts to avoid doing so.

The definitions of reasonable force potentially affect everybody – not just those in the security industry. Homeowners, teachers, emergency workers, retail staff and private citizens from all walks of life could be subject to legal ramifications should the need to defend themselves suddenly arise and the rules of reasonable force are not followed in the resultant struggle.

We must all be vigilant, at all times – and the ones we need to watch most closely of all, it seems, are ourselves.

1.   The Definition of Reasonable Force

 The definition of reasonable force is, by necessity, somewhat loose and open to interpretation. Essentially, the legal term ‘reasonable force’ describes the amount of force necessary to protect oneself or one’s property from being harmed or stolen by another.

Unlawful aggression, of any kind, may be met with reasonable force, but said force must be proportional to the threat being faced by the person using it. Reasonable force may be used as a defence in a criminal trial or to defend yourself if you are faced with a suit alleging tortious conduct.

As a private UK citizen, you have the right to protect your home from attack or invasion. You may do this by meeting a threat with a proportional and measured response designed to neutralize that threat.

In such and similar instances, protecting yourself ‘in the heat of the moment’ may involve the use of an object as a weapon. You may also apprehend an intruder to stop them escaping (i.e. by tackling them to the ground and safely restraining them until the police can arrive).

However, you must only do what you feel is necessary at the time. You are not permitted to cause undue harm upon the person, even if you believe they would have done so to you.

According to the UK Government, you do not have to wait to be attacked before defending yourself in your own home. However, you can (and likely will) be prosecuted if you continue to harm the intruder after the danger has passed, or if you pre-plan to trap an intruder instead of using the proper channels (i.e. police or private security firms).

As previously stated, there is no clear and simple definition of reasonable force, largely because the situations that require it are many and varied. As a general rule, you should not be inflicting more harm upon the other person than is absolutely necessary at the time – and your response need not always be proportional to the violence offered by the attacker or intruder. Reasonable force is a defensive, not offensive concept.

2.   Understanding Reasonable Force.

 To prove that any force used during a specific incident was reasonable, you must first demonstrate that the force used was necessary according to what you thought at the time.

So, if you can prove that the reasoning behind the initial assessment of the threat was sound and that you responded appropriately and proportionately to said threat, then you will have acted in accordance with the law, even if a considerable level of force was used.

Accordingly, when faced with the decision as to whether or not the amount of force used was reasonable or excessive, a court will consider two main questions.

1)   Did the person using force truly believe it was necessary to do so?

2)   Was the force used proportionate to the threat being faced?

If the answer to both questions is ‘yes’, then it is fair to conclude that the amount of force used was indeed reasonable – and a court will most likely arrive at this conclusion.

Armed with this knowledge, it is very worth asking yourself both questions if you find yourself in a situation that could potentially become violent.

Courts will also recognise the effect of the instinct known as the ‘fight or flight’ response (also known as hyper-arousal or acute stress response). This is a physiological reaction experienced by most animals when faced with a perceived threat. The reaction is caused by a discharge from the sympathetic nervous system. It results in the animal (in this case a human) becoming either uncharacteristically violent or else desperate to escape the situation. This can, of course, affect a person’s behaviour and judgement and the law takes this into account.

Recognition of ‘fight or flight’ is actually signed into UK law. Section 76(7) (a) of the Criminal Justice and Immigration Act 2008 reads:

“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) …evidence of a person’s having done what the person honestly and instinctively thought was necessary for a legitimate purpose constitutes strong evidence that only reasonable action was taken…”

Use of reasonable force is permissible under circumstances such as the following:

·       Protecting yourself or others from imminent danger.

·       Preventing a crime (such as assault or robbery).

·       Defence of your property.

·       Defence of your home.

·       Assisting the lawful arrest of a suspected criminal.

In the vast majority of other cases, use of force will not be considered reasonable or acceptable – and may even result in prosecution.

3.   The Definition of Excessive Force.

The term ‘excessive force’ may be defined as any action taken in the defence of oneself, one’s property or other people that exceeds the necessary amount of force required to nullify the threat being presented.

As we’ve seen, to be considered as an example of reasonable force, an action must be measured, as well as proportional to the threat being presented at the time the action was taken. Excessive force, however, would involve the use of a disproportionate amount of force – perhaps even outright aggression.

Examples of excessive force might include continuing to harm an intruder after they have been restrained or harming somebody who does not pose an immediate physical threat to you.

Other examples of excessive force might include physically restraining a person who is already complying with verbal commands, or even issuing verbal threats and intimidation.

4.   When is it Acceptable to use Reasonable Force?

You may use reasonable force to gain control of a situation that has –or appears about to – become violent. However, your responses must always be in proportion to the threat presented by the other person/people.

Restraint of the aggressor, rather than physically injuring them, should always be the goal. Your aim ought to be to put the person in a position whereby they can no longer present a threat. This can often be achieved without throwing a single punch. If necessary, you may perform a citizen’s arrest before contacting the police.

Legally speaking, you are allowed to use ‘pre-emptive force’ (i.e. acting to control the situation if you have reason to believe that things are about to become violent) as a form of self-defence. For example, if a person has clenched their fists and appears ready to throw a punch, you are allowed to take action to restrain them.

Things you should think about if you do find yourself considering the use of reasonable force include:

1)   Is there a need to use force?

2)   What is the attacker(s) size or build compared to your own?

3)   Will you stop using force when the situation is resolved?

4)   Are you using force maliciously?

These are the questions that will likely be asked of you in the event that a formal investigation or any legal proceedings take place, so it is very worth being aware of them before any incident occurs.

5.   When Does Reasonable Force Become Excessive Force?

If your actions are deemed to have been malicious or a calculated act of revenge, you could face prosecution for the use of excessive force. Reasonable force tactics (such as physical restraint) would be considered excessive in instances where the other person is not presenting a physical threat, or where force tactics continue after the threat has been neutralised.

Kicking or punching somebody who is unconscious or already incapacitated or chasing a person down with intent to cause harm are both examples of excessive force.

Even in instances where the person acting is not the initial aggressor, actions such as these still qualify as excessive, because the person taking them is no longer defending him or herself, but has instead gone on the offensive.

With regards to home invasion, the law in the UK does not expect (to use its own wording) “fine judgements” over the level of force used in the heat of a specific moment. It does, however, expect a person to act “honestly and instinctively” when faced with a potentially aggressive intruder. In most cases, intent to steal or damage property or else cause harm to the home’s occupants is implied by an act of forcible entry.

It is worth noting at this point that people and property are subject to different laws, which overlap in cases such as these. In effect, it can become a bit confusing to know what rights you actually have in cases of home invasion. What follows is a general rundown.

Should the intruder run upon being discovered, they are no longer presenting a direct physical threat to the homeowner/resident. However, reasonable force tactics (such as a running tackle) may still be acceptable should the resident wish to retrieve stolen goods or perform a citizen’s arrest.

These rules do not, however, give the homeowner carte blanche to act in any way they please during instances of home invasion. The definitions of reasonable and excessive force still apply, even in your own home.

If the intruder is killed during such an incident, this can actually be permissible, as long as the force that resulted in his or her death was reasonable and proportionate. However, if the death was as a result of excessive force, then manslaughter or even murder charges could (and very likely would) be brought against the resident.

6.   Better Methods of Conflict Resolution.

In many cases, situations with the potential to become violent can be resolved before violence even becomes an issue. The main tool at your disposal here is basic empathy for others.

Empathy can be difficult to achieve when a person is angrily shouting in your face, so a good suggestion would be to hone your natural ability to empathize with others in your day-to-day life.

Empathy is a natural ability. Our brains come complete with a collection of what are called mirror neurons. Mirror neurons are interesting in that they fire both when an animal acts and when that animal observes the same action performed by another. Some scientists are now arguing that the presence of mirror neurons is a large contributing factor to our ability to vicariously experience the emotions felt by others.

For example, we can easily feel sympathy for a person who is going through a painful separation from their partner. We may be familiar with these feelings ourselves and will likely use our own experiences in order to create a more complete understanding of their experience. This is a basic definition of sympathy.

Empathy, on the other hand, describes the ability of feeling an emotional engagement with a person’s predicament even if we have not experienced it ourselves. A lifelong teetotaller who finds him or herself unable to find sympathy for an alcoholic, for example, is lacking in empathy.

It is easy to notice the differences between other people and yourself. They look different to you, they act differently and they may exhibit preferences, characteristics and behaviours that seem totally alien to you. However, encouraging yourself to ‘step into another person’s shoes’ as they saying goes, can be invaluable when it comes to conflict resolution.

When confronted by a situation that has the potential for violence, ask yourself the following questions:

1)   What does the other person have to lose? (Are they in a rush to be somewhere important? Are they afraid of being embarrassed in front of their friends? Are they about to lose money or property? Etc.)

2)   How would YOU feel in their situation?

3)   Could there be something else going on in their life to make them aggressive and ill tempered?

4)   Are they experiencing symptoms of physical or mental illness that might explain some or all of their actions?

For example, if a person has just lost their job, or a friend or relative of theirs has recently passed away, this may cause that person to act in ways that would otherwise be considered ‘out of character’ for them.

Alcohol consumption and drug use too can become a factor in cases such as these. A person who would otherwise be polite and reasonable may become aggressive or even violent once alcohol is introduced into the situation.

In some cases, a person’s ego has simply gotten the better of them. This can happen to anybody. Have you ever tried to make a point about something, been proven wrong, but stuck to your guns in some way instead of simply apologising and backing down? It’s happened to everyone. This is because our egos make us the heroes of our own stories – we don’t like to see ourselves as flawed or capable of major errors. Sometimes, having empathy for others means stepping out of your own story for a chapter or two and seeing the other person as the hero – even if a by-product of this involves temporarily casting yourself in the role of villain.

There are many simple ways to boost your natural ability to empathise with others. The first step involves understanding and sanctioning a lot of your own emotions (yes, even the negative ones).

Understanding your own emotions and boosting your ability to empathise will greatly aid you in many areas of life, such as improving job performance, building conflict resolution skills, enjoying a more complete engagement in meaningful relationships (of all kinds) and being more effective in business dealings.

If you can improve your own ability to empathise, you will likely become a better communicator. As a result, the amount of instances in your life in which any kind of force is required will decrease dramatically.

7.   How to Assert Yourself.

It sounds like a contradiction, but it is entirely possible to be an assertive – even authoritative – presence whilst still being highly empathetic.

Increasing empathetic awareness does not turn a tough nut into a teddy bear; instead, it simply increases your understanding of the people around you and the situations in which you find yourself.

Understanding another person does not mean that you will allow them to become aggressive or take advantage of you, but it does help you to avoid situations in which they might try to do so.

There are many ways to become more assertive. As a brief, but important, aside, being assertive does not mean being aggressive; it simply means that you are confident, speaking clearly and with authority.

The following are a few tips.

1)   Don’t shout or raise your voice, just speak clearly and keep your tone low and steady. If you raise your voice, the other person may become tempted to raise their own voice in order to shout over you – aggression very often follows behaviour like this. 

2)   Listen keenly and actively to what is being said, but don’t allow others to monopolize the conversation. State your case in clear, simple terms.

3)   Always be respectful to others – and ask for that same respect in return.

4)   If the person’s aggression increases, double down on your assertiveness and make it clear that your patience is decreasing.

8.   Don’t Lose Focus!

It is very important that you don’t lose your temper with the aggressive person – yes, this is very hard to do, but it is not impossible.

When a person is overtaken by their emotions (good or bad), they lose sight of the matter at hand. In many cases, a person who has become aggressive has simply lost focus.

Try to get aggressive people to see what’s really important. If they’re with somebody else, such as a friend or romantic partner, it can help to remind them of this person’s presence. Most people, if given the choice, would definitely choose an evening at home with their friends or significant other over being arrested and detained at the local police station!

If possible, you can try to make the other person laugh. This disarms them utterly, making them far less likely to respond aggressively. A neat quip or one-liner, delivered at the right time, can diffuse many threatening scenarios. You want to be careful not to make light of the person or their situation, however, as this will only make things worse. Nevertheless, humour can build a useful bridge between people on opposing sides of a dispute.

It also helps to point out that the person has become aggressive. However, this must be done in a particular way, otherwise it can make them angrier. Simply stating “I’d appreciate it if you could lower your voice a little”, “I need you to try and calm down so I can help you” or some other non-combative statement can help people to see that they are losing focus and that negative emotions are clouding their judgement.

Promising to work with them to resolve their problem is one method. It also helps if you can verbally demonstrate that you understand and empathise with their predicament.

One final tip is to set consequences for the other person’s behaviour. This does not mean making threats. Explain, in a calm and clear manner, that if the person continues to speak and act in this way, you will be forced to take action (such as calling the police or escorting them off the premises). You can then remind the person that their actions are their own choice; that the metaphorical ball is in their court, so to speak. If they continue, they have chosen to accept the consequences. Once again, when people lose focus, they often forget that their actions can have repercussions. A simple reminder of this basic fact will often be enough to dispel aggressive behaviour.

As previously stated, it is important that you keep your focus. Don’t lose sight of your overall objective. If you want to convince the person to leave a specific area of their own volition, then be sure not to lose sight of this goal. If you simply need the other person to calm down, make this your focus.

By being assertive and increasing your abilities to empathise and communicate more effectively, you can avoid many instances of violence that would require the use of reasonable force to control. It turns out, rather more often than we might expect, that the most reasonable use of force is not to use force at all.