Court finds arrest unlawful despite rejecting only parts of police evidence

The High Court's decision in Watson v Chief Constable of Humberside Police [2025] EWHC 2544 (KB) provides important guidance on the limits of judicial fact-finding when a defendant's pleaded case is partially rejected. Mr Justice Lavender allowed the appeal on claims for assault, battery and false imprisonment whilst upholding the dismissal of the malicious prosecution claim.

Factual background

Police officers attended Christopher Watson's home in June 2017 after he telephoned stating his intention to self-harm. Officers found Watson in a communal garden area with a knife, which he had held to his throat. The officers deployed a taser, kicked Watson to dislodge the knife, and arrested him for affray and a Public Order Act section 4 offence.

The officers consistently maintained from 2017 through to trial in 2023 that Watson had lunged at them with the knife. Watson was acquitted at trial in November 2018, and subsequently brought civil proceedings.

The recorder's findings

At first instance, Mr Recorder Brain rejected the officers' evidence that Watson had lunged at them, pointed the knife at them, or moved quickly towards them. He found the officers' accounts to be embellished and unreliable. Nevertheless, the recorder dismissed all three claims, finding that:

• Watson had committed affray by standing whilst holding the knife
• The officers had reasonable grounds to suspect affray was being committed
• The officers acted in self-defence
• The arrest was lawful and necessary

The recorder reached these conclusions by identifying what he considered to be "really operating on the officers' minds", despite rejecting their actual stated grounds for suspicion and arrest.

The appeal decision

Lavender J held that the recorder had impermissibly departed from the respondent's pleaded case. The amended defence in paragraph 28 clearly specified that PC Crouch suspected affray because he had "seen the Claimant point a knife in his direction and walk towards him while shouting threats and adopting an aggressive posture." The recorder had rejected all of these factual allegations.

The Court emphasised the principle from Al-Medenni v Mars UK Ltd [2005] EWCA Civ 1041 that judges must adjudicate on the issues as pleaded and cannot reformulate a party's case. Whilst judges routinely accept parts of witness evidence whilst rejecting other parts, they must operate within the framework of pleaded issues.

Crucially, the appellant was prejudiced because the case was decided on grounds not explored in evidence. The officers were never cross-examined on alternative grounds for their suspicion or belief in the necessity of arrest. The question raised by the recorder after trial came too late to cure this procedural unfairness.

Lavender J also found that the recorder erred in finding Watson had committed affray—a matter never alleged by the respondent.

Malicious prosecution claim

The Court declined to interfere with the dismissal of the malicious prosecution claim. Ground 4 of the appeal, though successful in establishing absence of reasonable and probable cause, failed to address two essential elements: whether the officers were to be regarded as prosecutors (in the Martin v Watson sense) and whether they acted with malice.

These issues had not been adequately explored at trial, and there was no ground of appeal challenging the recorder's finding of no malice. The Court therefore could not disturb the dismissal of this claim.

The case will return to the County Court for assessment of damages on the successful assault, battery and false imprisonment claims.