There has been no sign of Amanda for 15 days

Pictures of the missing girl, known as Milly, will also be broadcast in petrol stations on forecourt television.

A spokesman for Surrey Police said the initiatives were made "in the hope that it will encourage Milly or anyone who thinks they may know where she is to call the police, her family or the helpline".

"We still need people to come forward with any information, however trivial or irrelevant they think it is, as we are following all lines of inquiry."

Amanda's picture will be featured on Ford's 40-feet long trucks next week.

Possible sightings

Detectives investigating the disappearance of Amanda are studying possible sightings of a girl fitting her description.

Two motorists told detectives they believe they saw Amanda, after the last definite sighting of the schoolgirl at about 1600 GMT on Thursday 21 March.

The girl, who fitted Amanda's description, was spotted near her home, wearing a school uniform, and looked as if she was crying.

Click here for a larger map of what happened Enlarge image

Detectives are keen to establish whether or not the girl was Amanda, and have appealed to the girl to come forward.

Detectives also want to speak to the driver of a blue Saab car, who was seen talking to a girl near to where Amanda was last seen.

"If you were that driver or that person talking to the motorist, please call us," said Detective Chief Inspector Stuart Gibson.

Detectives believe Amanda may have run away with, or been abducted by, someone she knew.

They have been carrying out painstaking searches of the three square mile area between the station, her home and nearby Hersham station, but have so far found nothing.

On Wednesday, police searched a nearby river where two boys said they saw a body, but said no body was discovered.

A blazer was found, but detectives from the Amanda hunt said it did not match her clothing.