Palmer v R,  AC 814; approved in R v McInnes, 55 Cr App R 551:
Any person may use such force as is reasonable in the defense of themselves, others, and in certain circumstances property.
The Criminal Law - Act 1967, Section 3:
A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting the lawful arrest of offenders or suspected offenders or of persons unlawfully at large.
Where necessary reasonable force can be used to restrain or control someone. Everybody has the right to defend themselves against attack providing they don’t use a disproportionate degree of force to do so. It must be reasonable in the circumstances, an absolute necessity, the minimum amount necessary, proportionate to the seriousness of the circumstances.
HEALTH & SAFETY AT WORK ACT
Health & Safety At Work - Act 1974, section 7:
Employees are required ‘to take reasonable care for the health and safety of himself and other persons who may be affected by his acts and omissions at work
Lord Griffith said in (1988) for the case Beckford v The Crown:
“A man or a woman about to be attacked does not have to wait for his assailant to strike the first blow, or fire the first shot, Certain circumstances may justify a pre-emptive strike”