A POLICE officer is facing jail after he was convicted of punching a 12-year-old boy in the face while he was in custody.

Pc Daniel Gaffney, 30, claimed he was acting in self defence after the aggressive youngster lunged at him while he was putting him in a cell at West Didsbury Police Station in November last year.

He denied common assault, but admitted he struck him with a forceful blow, which caused the boy's nose to gush with blood.

Deputy District Judge Timothy Gascoyne, sitting at Runcorn magistrates' court, rejected Gaffney's self-defence story and said he struck the slight 5ft boy because he had lost his temper.

He said the officer then lied to three superiors about what had happened, saying the boy had hit his head.

"You panicked because you realised your actions in the cell on that Saturday afternoon would almost certainly result in the end of your police career," the judge said.

The boy now 13, who cannot be named for legal reasons, had been arrested by another officer after threatening staff at a Manchester children's home with fence posts.

Sentencing was adjourned until late August while reports are prepared, but Gaffney was warned that custody was an option.