The techniques practiced in Ninjutsu can inflict serious injury and many are potentially lethal. It is therefore important to understand what constitutes “Reasonable Force” when protecting yourself and others, protecting property and in the prevention of crime.

What is reasonable force?

A person may use such force as is reasonable in the circumstances for the purposes of: –

• Self-defence
• Defence of another
• Defence of property
• Prevention of crime
• Lawful arrest

Ask yourself: Is the use of force necessary? Is there a need for any force at all?

Frequently Asked Questions on Self Defence

When can self defence be used?

Self defence can justifiably be used:

• To defend yourself
• In defence of another
• To protect property
• To prevent a crime being committed
• During a lawful arrest

Provided you only use “reasonable force”.

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

What is grossly disproportionate force?

If your action was ‘over the top’ or a calculated action of revenge or retribution, 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 I chase them as they run off?

This is no longer a situation of self-defence. However, you are still allowed to use reasonable force to recover your property and make a citizen’s arrest. Acting out of malice and revenge with the intent of inflicting punishment through injury or death would not be reasonable.

The above is based on:

Householders and the use of force against intruders
Joint Public Statement from the Crown Prosecution Service and the
Association of Chief Police Officers

For more information, read the full joint public statement from The Crown Prosecution Service and The Association of Chief Police Officers.

Remember that the police have a duty to investigate incidents involving death or injury.
You therefore have two fights to consider:

• The first is the physical fight in the heat of the moment to protect yourself.
• The second is potentially in court defending your actions, so only do what is necessary to protect yourself or others.