BBC North of England Correspondent Mike McKay: Police are taking this sighting very seriously

Rev Jack Cooper was working as a volunteer ticket collector on the North Yorkshire Steam Railway on Saturday when he came across Jeff and Jenny Bramley with Jade and Hannah Bennett on a "family" outing.

It was the first definite sighting since the girls were taken 16 weeks ago by the couple after being ordered to hand them back to Cambridgeshire social workers.

Jack Cooper: I told them to shut up

Mr Cooper said he saw five-year-old Jade screaming uncontrollably in a railway carriage, while her three-year-old half sister Hannah was "restless".

He said: "The couple seemed inadequate. She was just sitting there watching and he was trying to get them to be quiet but didn't seem to be making much of a job of it.

"I went across and intervened and told them, not in so many words, to shut up and be quiet."

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

He then told the girls a story about how noisy children frightened sheep and that seemed to do the trick, he said.

"I turned to the parents and said half-jokingly that I hadn't lost my touch. He looked a little bit put out but she didn't say anything.

"She looked appallingly thin, with very, very pinched cheeks and soft chin. I'd say she was anorexic."

Abandoned: Car found with clothing and documents

Detectives now hope to close the net on the missing family after finding their car a blue Honda Concerto - registration number G152 SHR - parked in York last Wednesday.

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 mechanics who may have worked on the car.

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

The family disappeared from their home in Ramsey, Cambridgeshire, in early September after an unsuccessful attempt to win custody through the courts. They took their passports and other documents with them.

Postal worker Mr Bramley, 34, and Mrs Bramley, 35, who have no children of their own, had been caring for the girls since March 1998.

Jade Bennett: Sighted on railway

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 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.