The BBC's John Andrew: Police received a good description

Police say Jeff and Jennifer Bramley have been spotted together for the first time with the children, Jade Bennett, five, and her sister Hannah, three.

Det Sgt Mark Nicholson of Cambridgeshire Police: "Please get in touch"

The family disappeared from their home in Ramsey, Cambridgeshire, in early September, after being told they might not be allowed to adopt the children. They took their passports and other documents with them.

But a spokesman for Cambridgeshire Police said the four had been seen on the North Yorkshire steam railway between Grosmont and Pickering on Saturday afternoon.

Jade Bennett: Sighted on railway

Their car, a blue Honda Concerto - registration number G152 SHR - was found abandoned near York station before the New Year.

Detectives are in the county following up the new lead.

They have been concentrating their search on the York area following the discovery of the car.

The BBC's John Thorne: "This is the first sighting in almost 16 weeks"

They believe it may not have been intentionally abandoned because the family had recently had new Pirelli tyres fitted, possibly as part of an MOT inspection.

Detectives have appealed to local machanics who may have worked on the car.

Coats belonging to Jade and Hannah were found in the boot along with documents belonging to the Bramleys.

Abandoned: Car found with clothing and documents

Concern has been rising for the welfare of the girls since the disappearance.

At one point a High Court Judge, Mrs Justice Hogg, made a direct appeal to the public for help.

Reported sightings of the family came from as far away as Ireland.

The Bramleys, who have no children of their own, had been caring for the girls since March 1998.

PC Pete Morley from Cambridgeshire Police talks to BBC News 24 about the latest sighting

They disappeared after an unsuccessful attempt to win custody through the courts.

The girls' natural mother, Jacqueline Bennett, has made a televised appeal for their safe return.

Anyone with information should contact the High Court Tipstaff, law enforcement department, on 0171 936 6000.