The BBC's Paul Barltrop: "Police forces across Britain are on alert"

Katey Caven, 38, was last seen when she was bundled into a black BMW car in Clarence Street, Bath and driven off. That was on Wednesday.

Two people phoned the emergency services after she shouted to them to call for the police.

About four hours later, Mrs Caven telephoned her sister, saying she had been abducted by her estranged husband, Milton Caven, 39.

Katey's sister received a frantic phone call

The phone was slammed down and Mrs Caven's call was traced to a service station at East Grinstead, East Sussex, where a member of staff confirmed that a distressed-looking woman accompanied by a man had just left the garage moments before.

Avon and Somerset police said they were anxious to trace Mrs Caven, of Bannerdown Farm, Bathford, near Bath, and her husband Mr Caven who owns a black BMW, registration M132 FDL.

'Stormy relationship'

Detective Sergeant Martin Walker said the couple, who married in November 1997, had had "a stormy relationship".

"What has brought this present situation about is not clear," he said. "Christmas and New Year can be a stressful time for some people and something has upset the balance.

"Things have not gone this far before and their family, and ourselves, are becoming increasingly concerned as time goes on. We are urging the couple to contact their family to re-assure them and us."

Other forces had been given details of the incident but so far there have been no reported sightings of Mrs Caven or the car.

Mr Caven is described as black, 6ft tall, with a dreadlocks hair style.

Mrs Caven is of mixed race, is slim, 5ft 7inches tall, with short, burgundy-coloured hair and brown eyes.