Two police officers saw a lorry being repaired by two men and causing an obstruction on the highway outside a garage.
The officers returned a few minutes later, saw the lorry had been moved into the garage, the officers entered the garage to enquire who was responsible for the obstruction.
The officers were told to leave the premises and that they could not be there without a search warrant. One of the police was in the act of producing his warrant card when one of the men struck him. He was convicted of assaulting and obstructing a police officer in the execution of his duty.
Both convictions were quashed on appeal because permission given to enter private property may be revoked which makes the visitor a trespasser.
The act of producing his warrant card was an assertion by the officer of a right to remain on the premises which right he did not have and therefore he could not be acting in the execution of his duty.
The judge held that although the officers entering the premises were not trespassers, they became trespassers they were told to leave, and thus, were not acting in the execution of duty.