Police are today investigating a hit-and-run in a supermarket car park that left a young woman with serious head injuries.

The incident happened in the Asda car park, off Drayton High Road, in Hellesdon, when a silver Vauxhall Corsa was leaving the store towards the Sweet Briar exit. Police said the vehicle hit a female pedestrian, before leaving the scene.

The 21-year-old woman, believed to be from the Norwich area, was taken to Addenbrooke's Hospital, in Cambridge, for treatment. The ambulance service said she sustained a serious head injury and required critical care.

Speaking yesterday, her partner, who did not wish to be named, said she had been in a coma following the incident. But he added that she had since regained consciousness and was now in a stable condition.

Officers later found and seized the vehicle believed to have been involved in the incident, which occurred at around 7.50pm on Thursday. Police said an 18-year-old man from the Norwich area has been arrested for failing to stop at an injury road traffic collision and on suspicion of causing serious injury through dangerous driving.

He has been released on bail until Saturday, April 9 to allow for further enquiries.

It is not known how fast the vehicle was travelling, but Asda said a 5mph speed limit is clearly signposted around its car parks.

A spokesman for the company said that an ambulance was called straight away and colleagues were on hand to help the woman until emergency services arrived.

The spokesman added: 'We're aware of an accident that happened at our Norwich store and are doing everything we can to assist the police with their enquiries.'

Anyone who may have seen the incident or anyone with information should contact PC Robert Conner at Wymondham Police Station on 101, Crimestoppers anonymously on 0800 555 111 or via their anonymous online form at www.crimestoppers-uk.org.