A police officer's career lay in tatters today after he was convicted of assaulting a drunk during an arrest.

CCTV cameras caught PC Andrew Davison twice kicking Thomas Robertson as he lay on the ground struggling with police officers.

He was convicted of common assault after District Judge Stephen Earl ruled he had used excessive force during the arrest a year ago. While passing sentence, the judge asked Durham Constabulary not to sack the officer.

''If in fact Mr Davison were to lose his job, and I trust that could well be, I think that is sad because I do believe this was a likely one-off occasion,'' the judge said.

Newton Aycliffe Magistrates' Court heard PC Davison had been called to assist a colleague who was having difficulty restraining Mr Robertson.

PC Colin Goodchild asked for back up during an incident at a taxi rank on North Road, in Durham City, in the early hours on November 26, 2004.

As Mr Robertson lay struggling on the ground, PC Davison, who worked in the city, was caught on CCTV cameras repeatedly kicking the 35-year-old Scot.

Mr Robertson, a mining engineer, from Fife, central Scotland, was on a night out in Durham while working on a contract with Northumbrian Water.

He was subsequently fined £125 by North Durham magistrates for resisting arrest by PC Goodchild, and for being drunk and disorderly.

He was also ordered to pay £35 compensation to PC Goodchild and £35 costs.

Mr Robertson, who wrote to the court saying he did not want to see PC Davison jailed, said he suffered an injured arm and a number of bruises to his body during the incident last year.

The city centre's CCTV captured images of the arrest and PC Davison was reported to his superiors by civilian staff monitoring the camera network.

PC Davison, 32, who lives in Sunderland, denied common assault saying he felt he took the necessary action to subdue Mr Robertson, who was struggling violently.

After a two-day trial last month, the district judge found PC Davison guilty and ruled he had used excessive force to arrest Mr Robertson.

Sentencing the officer to 200 hours of community service and ordering him to pay £600 costs, the judge said: ''I take into account PC Davison's exemplary service record, no previous convictions and his good character.''

Afterwards, defence solicitor Stephen Thornton said his client intended to appeal against the conviction.