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On 28 July 2025 Justice Bourne sitting in the High Court, handed down judgment in the appeal of ALK (1) ECN (2) v The Chief Constable of Surrey Police, restating the law on necessity for an arrest to be lawful under s24 Police and Criminal Evidence Act 1984 (PACE). This article focuses on what officers need to consider to ensure that an arrest is lawful and not open to challenge on necessity grounds.
Background
The two claimants were married and serving officers with the Metropolitan Police. They had three children, the middle of whom was a 13 year old boy (ABD) who had a history of challenging behaviour. He had repeatedly been late home from school and had missed a dental appointment. A birthday party had been planned for him for the weekend of 9-10 March 2019. On 8 March 2019 he attended a Youth Centre. His mother (the first claimant) asked him to come straight home from school but he did not return until two hours later and failed to answer his phone. When he returned she told him she had been very worried about him and that his party would be cancelled. He stormed into his room and kicked things around. Paragraph 5 of the judgment notes that the first claimant stated that she gave him a ““light smack on the left cheek” which “was not hard and did not cause any injury or leave any mark”.” His father (the second claimant) was asleep when this occurred. The second claimant was arrested the following day upon collecting his son from the youth club. He was taken into custody and his detention authorised at 9pm.
ABD remained at the youth centre and was later driven by officers to stay with his grandmother.
The first claimant was at home when officers arrived at 9.39pm and arrested her. She signed an agreement under s20 of the Children Act 1989 permitting her children to be looked after in alternative accommodation by the local authority if necessary. Having spoken to the eldest child (the youngest child was asleep) the attending Detective Constable and a member of the Emergency Duty Team “concluded that there was no risk of any harm to either of them and that it would be unnecessarily disruptive to remove them”. It was agreed that both children should remain at home with a grandparent. A Detective Constable and a social worker spoke to the younger sibling the next day. The first claimant was taken to custody and her detention authorised at 10.51pm
The second claimant was released after 7 hours and 32 minutes. The first claimant was released after 7 hours and 15 minutes. Both were to remain under investigation with no conditions.
ABD returned home the following day and the claimants were told that no further action would be taken. Both claimants claimed that their arrests were unlawful because they were not necessary, amounting to false imprisonment, battery, and trespass.
The general principle
Section 24 Police and Criminal Evidence Act 1984 (PACE) sets out the conditions that must be present for an arrest to be lawful: s24(1) and (2) requires that the officer may arrest without a warrant anyone who they reasonably suspect is or is about to commit an offence. Section 24(4) states that the power of summary arrest “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.”
The reasons set out in subsection (5) are exhaustive and 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;
(iii) causing loss of or damage to property;
(iv) committing an offence against public decency (subject to subsection (6)); or
(v) causing an unlawful obstruction of the highway;
(d) to protect a child or other vulnerable person from the person in question;
(e) to allow the prompt and effective investigation of the offence or of the conduct of the person in question;
(f) to prevent any prosecution for the offence from being hindered by the disappearance of the person in question.”
Code G accompanying PACE aids in the understanding of this statutory power. Paragraph 1.3 of the Code states that “use of the power [of arrest] must be fully justified and officers exercising the power should consider if the necessary objectives can be met by other, less intrusive means.” Absence of justification “may lead to challenges should the case proceed to court and “could also lead to civil claims against police for unlawful arrest and false imprisonment.”
Paragraph 2.4 of Code G makes clear that the decision to arrest is an operational decision at the discretion of the arresting officer as to what action they could take at the point of contact with the individual; the necessary criterion which applies; and whether to arrest, report for summons, grant street bail, issue a fixed penalty notice or take any other action that is open to the officer.
Decision at lower court
At first instance, HHJ Simpkiss found for the Chief Constable, holding that the arresting officers held objective reasons for believing that the arrests were necessary in order to protect a child and to ensure a prompt and effective investigation. The officers believed that all three children were at significant risk and required urgent protection from the claimants about who they knew very little. Whilst there was no evidence that alternatives to arrest had been considered, this might have risked collusion between the claimants and interference with evidence.
Decision of the Appeal Court
The main grounds for appeal was that the judge erred in finding that the officers’ beliefs that arrest was necessary were objectively reasonable.
Justice Bourne noted that there had been no reason identified as to why voluntary interview had not been considered. At the time of the arrest, “the alleged victim was safe, in the presence of officers and a social worker.” The second claimant had not been accused of any contact offence and the suspects were entirely cooperative. Accordingly, it could not be argued that there was “an “operational” justification for an arrest at the time.” The Judge stating that “[t]he situation was under control.”
The Judge concluded that “the police must assess the circumstances and make rational decisions as to whether coercive measures are needed or not.”
In holding that the arrests were unlawful, the Judge concluded that “the “plain risk” of liability following from the officers’ omission to consider alternatives to arrest has eventuated.” Adding that [m]erely referring to the need to protect children and to protect the integrity of the investigation was not enough.”
Comment
This judgment makes stark that necessity is seen as an important protection of the rights of citizens. To ensure that an arrest is necessary, officers must carefully consider the actual reason for arrest and whether there is an alternative. Depriving someone of their liberty must be a last resort. There must be an evaluation as to whether voluntary interview would achieve the objective that the officer wishes to secure. This assessment should be documented as soon as reasonably practicable. If voluntary interview is not considered appropriate, the officer should explain why.
Public sector
United Kingdom