The Commissioner of Police for the Metropolis v MR

Under section 24 of the Police and Criminal Evidence Act 1984, reasonable suspicion is a low threshold, but the necessity of arrest imposes a distinct and demanding safeguard. The officer must honestly believe that arrest is necessary for a statutory reason, and that belief must be objectively supported by reasonable grounds based on the information known at the time. The court conducts its own objective assessment. It must scrutinise the particular officer’s reasoning without substituting an abstract view of what any officer might have done. Voluntary attendance at a police station is an important factor. Where interview, identification and evidence-gathering can reasonably proceed without arrest, arrest may be unnecessary and unlawful.

The Commissioner appealed against a decision of Her Honour Judge Baucher following a trial in the Central London County Court. The judge had awarded MR £2,750 for false imprisonment and assault after finding that his arrest for suspected harassment was unlawful. She accepted that the officer reasonably suspected MR of harassment but held that the officer’s belief in the necessity of arrest was not objectively justified.

MR cross-appealed, contending that there had also been no objectively reasonable grounds for suspicion. The central issues were whether suspicion of harassment was objectively justified and whether arrest was objectively necessary for the prompt and effective investigation of the offence or conduct.

1. Reasonable suspicion. The appeal court had to reach its own conclusion on whether reasonable grounds existed, while giving appropriate weight to the trial judge’s assessment where the task had been correctly approached: Alford v Chief Constable of Cambridgeshire Police [2009] EWCA Civ 100. The threshold for suspicion is low. The officer genuinely suspected MR of harassment, and the complainant’s repeated unwanted contact and approach to the police could objectively support an inference of alarm or distress. The officer’s suspicion was therefore objectively reasonable.
2. Necessity. The applicable test from Hayes v Chief Constable [2012] 1 WLR 517 has two stages: the officer must honestly believe that arrest is necessary for a statutory reason, and that decision must, on objective review of the information known at the time, be supported by reasonable grounds.
3. The objective limb is not a separate, highly deferential Wednesbury review asking whether any reasonable officer could have made the decision. It incorporates the relevant reasonableness principle but requires careful judicial scrutiny of the particular officer’s grounds. Necessity is more than desirability, convenience or mere reasonableness. The safeguard exists to protect liberty and maintain police accountability.
4. Whether a voluntary attendee needs to be arrested is fact-specific. The officer should consider alternatives, including voluntary interview, establishing identity and obtaining relevant evidence without arrest. An officer who gives no proper consideration to such alternatives risks having no objectively reasonable grounds for believing that arrest is necessary.
5. MR had attended voluntarily, and the police could interview him, establish his identity and seek his telephone without arrest. The suggested reasons, individually and collectively, did not establish objective necessity. The arrest was unlawful. The appeal and cross-appeal were dismissed.

• High Court (Queen’s Bench Division): appeal and cross-appeal dismissed. The decision of the Central London County Court was upheld.
• Central London County Court: on 3 July 2018, Her Honour Judge Baucher found the arrest unlawful and awarded MR £2,750 for false imprisonment and assault. Permission to appeal was refused on 14 September 2018.