which puts someone in immediate danger of injury or property in immediate danger of damage". The general power of all persons to arrest can also be derived from statutory sources. Section 101 of the Criminal Procedure Ordinance (Cap.221) stipulates that any person may arrest without warrant any person whom he may reasonably suspect of being guilty of an arrestable offence. An arrestable offence in Hong Kong refers to an offence for which the sentence is fixed by law or for which a person may be sentenced to imprisonment for a term exceeding 12 months. Section 101A of the Criminal Procedure Ordinance also allows any person to use reasonable force when effecting or assisting a lawful arrest. The power of the police to arrest is much more extensive than that for citizens. They have the unqualified power to arrest pursuant to a warrant, and the police officer effecting the arrest is not responsible for any irregularities in the warrant as long as he is acting pursuant to it. A police officer can execute a warrant notwithstanding the warrant is not in his possession at the time, but the warrant shall, on the demand of the person affected, be shown to him as soon as practicable after the arrest. If no warrant is obtained, the police can only effect an arrest pursuant to section 50 of the Police Force Ordinance (Cap.232). Section 50 allows a police officer to apprehend any person who (i) he reasonably believes will be charged with or who (ii) he reasonably suspects of being guilty of any offence for which the sentence is fixed by law or for which a person may be sentenced to imprisonment or if the service of a summons is impracticable. The constitutionality of this provision was reviewed in Yeung May-wan and Others v. HKSAR. The Court held that, in order to be compatible with Article 28 of the Basic Law, the first limb must be read as encompassing the second and did not eliminate the requirement for reasonable suspicion of guilt. The suspicion of guilt must be objectively reasonable, and the facts known by the police officer must be such that, if true, they would constitute all the elements of the offence in question. On the facts of that case, it was held that the arrests were not lawful and constituted false imprisonment as the police officers did not have in mind the