Reflects respect for the right to liberty
(1) An important qualification, which very much reflects respect for the right to liberty, is the requirement which applies to all normal arrest powers that they can only be exercised if some for of "reasonable suspicion" is first established. The precise meaning of this term is rather vague, but it basically means that the arresting officer must be sure subjectively there is some evidence against the detainee and it must be objectively the case that the evidence on the officer’s mind would have been enough to convince a reasonable bystander that it was reasonable to make an arrest. This does not mean there has to be proof of guilt beyond reasobale doubt (or even on the balance of probabilities). But it does mean there has to be good objective reasons for picking on the person to be arrested - the fact that he is a previous offender known to the police or is cheeky or is from a particular racial or ethnic group is not enough.
(2) According to PACE section 17, the police can enter private premises in order to make arrests:
Police and Criminal Evidence Act 1984, s.17
Entry for purpose of arrest, etc.
17. - (1) Subject to the following provisions of this section, and without prejudice to any other enactment, a constable may enter and search any premises for the purpose -
(a) of executing -
(i) a warrant of arrest issued in connection with or arising out of criminal proceedings; or
(ii) a warrant of commitment issued under section 76 of the Magistrates' Courts Act 1980;
(b) of arresting a person for an arrestable offence;
(c) of arresting a person for an offence under -
(i) section 1 (prohibition of uniforms in connection with political objects), ... of the Public Order Act 1936;
(ii) any enactment contained in sections 6 to 8 or 10 of the Criminal Law Act 1977 (offences relating to entering and remaining on property);
(iii) section 4 of the Public Order Act 1986 (fear or provocation of violence);
(iv) section 76 of the Criminal Justice and Public Order Act 1994 (failure to comply with interim possession order);
(ca) of arresting, in pursuance of section 32(1A) of the Children and Young Persons Act 1969, any child or young person who has been remanded or committed to local authority accommodation under section 23(1) of that Act;
(cb) of recapturing any person who is, or is deemed for any purpose to be, unlawfully at large while liable to be detained -
(i) in a prison, remand centre, young offender institution or secure training centre, or
(ii) in pursuance of section 53 of the Children and Young Persons Act 1933 (dealing with children and young persons guilty of grave crimes), in any other place;
(d) of recapturing any person whatsoever who is unlawfully at large and whom he is pursuing; or
(e) of saving life or limb or preventing serious damage to property.
(2) Except for the purpose specified in paragraph (e) of subsection (1) above, the powers of entry and search conferred by this section -
(a) are only exercisable if the constable has reasonable grounds for believing that the person whom he is seeking is on the premises; and
(b) are limited, in relation to premises consisting of two or more separate dwellings, to powers to enter and search -
(i) any parts of the premises which the occupiers of any dwelling comprised in the premises use in common with the occupiers of any other such dwelling; and
(ii) any such dwelling in which the constable has reasonable grounds for believing that the person whom he is seeking may be.
(3) The powers of entry and search conferred by this section are only exercisable for the purposes specified in subsection (1)(c)(ii) or (iv) above by a constable in uniform.
(4) The power of search conferred by this section is only a power to search to the extent that is reasonably required for the purpose for which the power of entry is exercised.
(5) Subject to subsection (6) below, all the rules of common law under which a constable has power to enter premises without a warrant are hereby abolished.
(6) Nothing in subsection (5) above affects any power of entry to deal with or prevent a breach of the peace.
Criminal Law Act 1967, s.3
Use of force in making arrest, etc.
3. - (1) A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large.
(2) Subsection (1) above shall replace the rules of the common law on the question when force used for a purpose mentioned in the subsection is justified by that purpose.
Search of Premises
The police can enter premises without the occupier's permission to make a search if;
a warrant has been issued by a Magistrate, the warrant must be shown before the search starts R v Longman (1988) In this case the police knew it would be difficult to gain entry to a property where they wished to search for drugs so they sent a undercover policewoman posing as a delivery driver from Interflora to get the occupants to open the door. Once the door was open the police burst in without showing the warrant and without saying they were police officers. The Court of Appeal held that the search was still lawful in such circumstances.
it is necessary in order to arrest a person named in an arrest warrant or to recapture an escaped prisoner. The police must give anyone present the reason for the entry. In O'Loughlin v Chief Constable of Essex (1998) the police forced their way in without explaining it was in order to arrest Mr O'loughlin's wife. This made the entry unlawful and Mr O'Loughlin was able to sue the police for damages.
it is believed that there is evidence relating to an arrest. It was held in R v Badham (1987) that this power must be exercised immediately after the arrest, the police cannot return to the premises a few hours later to make the search.
The police can enter premises without a search warrant if the occupier of the premises gives them permission to do so. This consent must be given in writing and if withdrawn at any time the police must stop their search and leave the premises.
If the police exceed any of their powers to enter and search premises then any person affected may bring a claim against the police in the civil courts. If the police obtain any evidence as a result of an unlawful search then they may still be able to use it against the defendant in court. The defence can argue that it should be inadmissable under s78 PACE, ultimately it will be for the Judge or Magistrate to decide if the evidence should be used by the prosecution.