An off-duty police officer underwent two operations after he was run down by a car in a late night hit-and-run incident, a force spokesman said today.

The 20-year-old, who has not been named, was hit by a silver Vauxhall Astra which had already struck two other people following an altercation in Middlesbrough town centre.

The officer, less than a year into his job, suffered a shattered left knee cap and had a bone graft taken from his hip to help its reconstruction. He had another operation on a leg fracture.

His condition at James Cook University Hospital was ''comfortable'' today.

Detective Sergeant Keith Dee said the officer had gone over to speak to the car's three occupants after two men were run over following a row at about 2.30am on Tuesday.

One man suffered a broken wrist in the incident, which happened near Jumping Jacks bar in Corporation Road.

Shortly after the officer spoke to the driver, the car moved off, turned round and drove at the policeman, knocking him and a friend to the ground, before it sped away.

The car's wing mirror was knocked off and left at the scene.

Mr Dee said: ''Someone must know this driver and have seen that the car suffered damage.

''This is a serious incident but it could easily have been a lot worse.''

The car was driven by a slim, white man, in his early 20s, with short, light-coloured hair which was gelled and spiked.