What is "Reasonable Force"?


What is Reasonable Force?

Have you ever asked this question and been left even more confused by the answer?

You are probably aware that the law allows us to use reasonable force in certain circumstances; eg. self-defence. You probably also know that there is a fine line between what is ok and what isn’t.


Picture the scene…Class full of students discussing self-defence and someone asks:

“So what is Reasonable Force?”

Trainer: “Good question… It depends on the circumstances”

Student: “Fair enough, but how do you define it?”

Trainer: (squirming just a little now) “Well it depends on lots of things like what level of force is being used against you, how big they are compared to you, how skilled they are and a whole range of other factors.”

Decent answer and of course our “expert” is right, all of those things are important, but it’s still a bit wooly. Seems open to which way the wind is blowing! The student persists…

Student: “But how do the courts decide on what’s reasonable or not?”
Trainer: “They take all the factors into account in making their decision, they will consider all of those things”

For that last response read: “Who knows…

In fairness to our trainer the concept of reasonable force is difficult to define, and for a lot of people it is a very “grey” area.

Our legal system isn’t so prescriptive as to say:
If you are attacked with a right hook then you may respond with a block and right hook of your own and no more. If you do then that’s reasonable force. But if you duck and stamp on his foot instead, that’s unreasonable…GUILTY- loose your job and go to jail.

While some may view this lack of clarity as a weakness, I believe it is a great strength. It would be ridiculous to expect everyone to react in exactly the same way without considering the individual’s personal characteristics and their reading of the circumstances or threat they were under at the time.

The reality is that situations involving physical force can happen very quickly and be highly emotionally charged. Responses are often without clear thought due to elevated heart rates and the physiological changes that occur when we are stressed.

So what is the answer?

How do the courts decide what’s reasonable?

The concept of “Reasonable Force” appears in (among others) common law; Section 76 Criminal Justice and Immigration Act 2008 (which confirms the basic principles of self-defence under common law) and Section 3 Criminal Law Act 1967.

There are two key questions the courts will consider. It’s helpful to understand them so that we can ask ourselves these questions BEFORE we use force (accepting it’s not always possible given the circumstances).

Question 1: Did you honestly believe you needed to use force?
Question 2: Was it proportionate?

If it’s Necessary (Q1) and Proportionate (Q2) then it’s Reasonable

Ok, imagine you are walking in a poorly lit area of town and a man with his face covered by his hoody, sneaks up and tackles you to the ground. He is a lot bigger than you and very aggressive. You are scared out of you mind, believing you’re being attacked and react instinctively by pushing an open palm out to his face, giving him a nose bleed.

Question 1: Did you honestly believe you needed to use force?

The courts will first decide on whether they believe that your version of events was what you HONESTLY believed at the time. Did you really believe you were being attacked by a stranger and were in imminent danger, and did you believe you needed to use force to avert that danger?

Generally speaking we are allowed to use force to:

  • Protect ourselves or others from imminent danger
  • Defend your property
  • Preventing Crime (eg Assault, damage etc)
  • Effecting /assisting in lawful arrest of offenders/suspected offenders or persons unlawfully at large

If we don’t NEED to use force but do anyway then that WILL NOT be reasonable, EVEN IF IT WAS PROPORTIONATE TO THE RISK. We didn’t need to do it, there was another way we could have handled it and we knew it!

The next question to ask is:
Question 2: Is what you did proportionate?

The Macmillan Dictionary defines “proportionate” as” correct or suitable in size, amount, or degree when considered in relation to something else”

A useful way to look at proportionality is:

Likely harm caused by the attack if you did nothing
Likely harm caused by your response

So in our example above:

What is the likely harm if you did nothing?
Being tackled to the ground presents a very real risk of hitting your head on the floor/pavement which would result in unconscious and who knows what else!
What was the likely harm caused by what you did?
Pushing the attacker’s face wouldn’t normally cause injury, perhaps reddening of the skin and bruising. Bloody nose was an unintended consequence.

In our scenario, the use of force was NECESSARY and PROPORTIONATE therefore it is highly likely to be deemed REASONABLE. Force was used to prevent a greater harm.

But are we expected to measure “pounds per square inch” of force when we are under attack?

For example, he’s using X force so I can only use X in response. The simple answer is NO.

The courts recognise the effect of what is commonly known as “fight or flight”. It’s even written into law.

Section 76(7) (a) of the Criminal Justice and Immigration Act 2008 says:
“..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…”

As a closing thought… If you did ever use physical force, would you be able to explain what you did and why you did it to 12 strangers? And would that group of strangers (for argument’s sake let’s call them a jury) agree that what you did was about right?

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About the Author

Terry is Director and Head of Training at Oakwood. He helps clients promote a proactive, rather than reactive approach to both personal safety and the positive mental health of their staff. He has over 12 years teaching experience in these areas, and advises organisations in the development of appropriate risk assessment and policy.