First, you have a right to be informed by the police officer of the reason for arresting you. If the police officer fails to tell you the reason at the time of the arrest, the arrest is generally unlawful. If, however, you try to run away or the situation is such that it is impractical for the officer to tell you the reason, then the officer may inform you the reason at a later time after the arrest.

Secondly, you have a right to silence. Immediately after the arrest, the police must inform you of your right to remain silent. The police officer will caution you by saying, "You are not obliged to say anything unless you wish to do so but whatever you say will be put into writing and may be given in evidence." You may therefore choose whether or not to answer any questions posed by the police (except that you may need to provide your name and address to the police).

You should also note that under the Criminal Procedure Ordinance, any person effecting an arrest may use such force as is reasonable. What constitutes reasonable force depends on the circumstances. A police officer may, for example, employ handcuffs or other means of restraint where it is necessary to prevent escape. The Police Force Ordinance also allows the police officer to use all means necessary to effect an arrest if the suspect forcibly resists or attempts to evade the arrest.

The police may arrest a person according to a warrant issued by a Magistrate. For example, an arrest warrant may be issued if an accused person does not appear in Court when he is due to answer a charge.

However, an arrest warrant is not always necessary. Under the Police Force Ordinance, a police officer can "apprehend" (i.e. arrest) a person if he reasonably suspects the person being arrested is guilty of an offence. Whether there is such a reasonable suspicion in a particular case is to be determined objectively by reference to facts and information which the arresting officer has at the time of the arrest. It is not necessary that the officer knows the exact statutory provision that the suspect has violated, so long as the officer reasonably suspects that the suspect has done something amounting to an offence.

If the police merely ask me to go to a police station to assist with their investigation, am I obliged to go? Can they detain me inside the station? When you are simply asked to assist in an investigation, you are under no legal obligation to assist or go to the police station. You are free to decide whether you wish to assist on a voluntary basis, and you may choose to leave at any time. However, if the police formally arrest you, then you must go with them to the police station.

Stopping and questioning

Under section 54(1) of the Police Force Ordinance, it is lawful for a police officer to stop a person who is acting in a suspicious manner. The police officer may require that person to produce proof of identity (i.e. by showing a Hong Kong ID card or passport), and detain that person on the spot for a reasonable period to make enquiries into whether or not the person is suspected of having committed any offence at any time. What constitutes a "suspicious manner" is based only on the subjective assessment of the police officer. However, the police officer must, in fact, have a genuine suspicion.

The Public Order Ordinance permits a police officer to require any person to produce proof of his identity for inspection for the purpose of preventing, detecting or investigating any offence. A failure by that person to produce proof of identity under these circumstances constitutes an offence.

The police and immigration officers also have power under the Immigration Ordinance to demand any resident in Hong Kong aged 15 or above to produce proof of his identity for inspection. A failure by that person to produce proof of identity as required without reasonable excuse constitutes an offence. It should be noted that this provision does not apply to foreign visitors who are staying in Hong Kong for not more than 180 days.

The police have the power to question anyone in accordance with the above rules. On the other hand, the common law as well as the Hong Kong Bill of Rights Ordinance (Cap. 383) provide that a person has the right not to be compelled to testify against himself or to confess guilt, i.e. every person in Hong Kong has the right to silence. By virtue of that right, a person may in general refuse to answer any question posed by a police officer. However, the driver of a vehicle who is suspected of committing a road traffic offence or being involved in a traffic accident must give his name, address and driving licence number to the police upon request.