Mossop v Director of Public Prosecutions

An arrest is lawful only where the officer has reasonable grounds to suspect that the facts known to him satisfy all material elements of the offence relied upon. It is insufficient to suspect that some related conduct occurred if an additional statutory requirement remains unsupported. For possession of an offensive weapon, that includes reasonable grounds to suspect possession in a public place and an offensive purpose. Where justices direct themselves on a materially incomplete issue, an appellate court will not go behind their findings to supply an alternative basis for the arrest. The conviction must be quashed, although a different factual basis might have justified the arrest had it been investigated and found.

The claimant appealed by way of case stated against his conviction by justices at Carlisle for two offences of resisting arrest. The arrests followed information that he had threatened occupants of a property with a hammer. When officers found him in the street, he surrendered a hammer and was arrested for possession of an offensive weapon.

The defence argued that the officer lacked reasonable grounds to suspect the commission of an offence because there was no evidence that the earlier conduct occurred in a public place or that the hammer was carried for an offensive purpose. The justices rejected the submission of no case to answer, and the claimant pleaded guilty. The central question was whether the officer’s failure to satisfy himself that the threats occurred in a public place rendered the arrest unlawful.

1. Appeal allowed. The justices had erred in treating the issue as whether the officer had reasonable grounds to suspect that an arrestable offence had been committed at Friars Close.
2. The relevant question was what was in the officer’s mind when he made the arrest and whether, on the information available, he had reasonable grounds for suspecting that the complete offence had been committed. For possession of an offensive weapon under Prevention of Crime Act 1953, section 1(4), the material requirements included possession in a public place and possession with an offensive purpose.
3. The court applied the reasoning in Chapman v Director of Public Prosecutions [1989] 89 Cr App R 190. As in that case, suspicion of conduct falling short of the complete arrestable offence could not justify the arrest.
4. The justices had made no finding that the officer had reasonable grounds to suspect that the claimant was carrying the hammer in a public place for an offensive purpose. The court could not go behind that finding or reconstruct the basis of the arrest.
5. The circumstances might have supported a different suspicion, namely that the claimant continued to possess the hammer in the street intending to use it offensively if approached by the earlier victims. The officer was not questioned sufficiently about that possibility, and the prosecutor did not recall him. That alternative could not cure the defective decision actually made.

• High Court (Administrative Court): Appeal by way of case stated allowed against the claimant’s conviction by Carlisle justices on 14 October 2002.