According to the charity Liberty, police can arrest you to prevent you from
suffering physical injury yourself – for example, if your behaviour might provoke others to assault you, so you need to be arrested for your own protection
What provisions govern the powers to arrest in such circumstances?
The Police and Criminal Evidence Act 1984 - Part III - Section 24 states :
(4)But the power of summary arrest conferred by subsection (1), (2) or (3) is exercisable only if the constable has reasonable grounds for believing that for any of the reasons mentioned in subsection (5) it is necessary to arrest the person in question.
(5)The reasons are—
(a)to enable the name of the person in question to be ascertained (in the case where the constable does not know, and cannot readily ascertain, the person's name, or has reasonable grounds for doubting whether a name given by the person as his name is his real name);
(b)correspondingly as regards the person's address;
(c)to prevent the person in question—
(i)causing physical injury to himself or any other person;
(ii)suffering physical injury;
