Police enforcement can at times be controversial, particularly when politicians are involved.
After police officers removed a Democratic Party district councillor, Ted Hui Chi-fung, from last month's meeting of the Central and Western district council's working group on civic education, some claimed they had gone too far. Hui was ejected after a vote by his fellow councillors, who apparently objected to him and his party colleague Ng Siu-hong filming their discussion of how to allocate HK$250,000 to promote the Basic Law.
Hui and Ng "kept filming other members, which provoked them", the working group chairman Sidney Lee Chi-hang said, leaving him no option but to eject them to ensure that the meeting continued peacefully.
Police Commissioner Andy Tsang Wai-hung insisted his officers had acted lawfully in removing Hui, and that they had simply maintained the "peace in society". Tsang, presumably, was referring to the duty of the police, under the Police Force Ordinance, to take lawful measures to "preserve the public peace" - although reporters seeking clarification were confounded when Tsang told them to get their own legal advice.
While the police have a statutory power to apprehend any person they reasonably suspect of being guilty of an offence punishable with imprisonment, they can also, under the common law, use reasonable force to prevent a person committing a breach of the peace. This, apparently, was what Tsang meant.
The essence of a breach of the peace lies in violence or threatened violence. A breach arises whenever harm is done or is likely to be done to a person or in their presence to their property, or a person is in fear of being so harmed through an assault, a riot or other disturbance. Someone may provoke a breach without any violence or threat of violence by them, if the natural consequence of their conduct is violence by a third party.
A breach of the peace can occur in a private or public place. So it was open to the police, if they feared an imminent breach, to remove Hui physically even if - as denied by the chairman - a decision had been taken to hold the meeting behind closed doors. An officer, like an ordinary citizen, may take reasonable steps to stop a person who is breaking or threatening to break the peace, such as detaining them, even without an arrest warrant.
But it does not suffice for an officer simply to claim he feared a breach of the peace and so acted to prevent it. The facts must show he reasonably anticipated a real, not a remote, possibility of a breach occurring if he did not step in.
The power of arrest arises where a breach occurs in the presence of the officer, or where he reasonably believes a breach is about to happen, or where a breach has already occurred and he reasonably believes it will recur. After all, the public expect the police not only to arrest an offender, but also to prevent an offence occurring. The common law, while recognising the importance of due process and the avoidance of unlawful detention, gives the police the power to achieve this.
A breach of the peace is not an offence, but its effects - if not prevented - may result in a crime, such as assault or criminal damage. A breach may constitute an element of another offence, such as disorder in a public place, which is often used as grounds to arrest protesters.
Although a person cannot be prosecuted for committing a breach of the peace, a complaint may be laid before a magistrate, aimed at stopping them from committing further breaches. The magistrate, after inquiry, may bind the person over to keep the peace if they conclude there are reasonable grounds for believing the person may be involved in a future breach of the peace. Someone who is bound over must provide a monetary deposit, typically for up to a year, which may be forfeited if they misbehave during that time.
The exact circumstances in which the police came to eject Hui are not wholly clear and may yet be subject to scrutiny. If, as Tsang claimed, they had acted lawfully to ensure a peaceful situation because of reasonable concerns on their part, it would seem they were simply applying their established common law power to keep the peace, which is in the public interest.
Grenville Cross SC, the former director of public prosecutions, is an honorary professor of law at the University of Hong Kong and vice-chairman of the International Association of Prosecutors senate