This set of three Ford car keys was found in the grass verge very close to where Melanie's remains were found.

We need to establish if they are connected in any way to Melanie's disappearance or if there is an innocent reason for their being found at that location.

The keys would have fitted a ford vehicle manufactured from around 1995 - 1996 and are connected together with a black plastic tag which bears the identification number T144213.

Police have distributed leaflets appealing to people who use the popular parking area at the lay-by near Tortworth, at junction 14. They particularly want to hear from anyone who had their car broken into while parked there.

Det Supt Mike Courtiour, said: "We have received information that the keys were stolen from a car parked there and then thrown away, but we can't conclusively say that's what happened. I'm asking drivers to remember if, sometime over the past 13 years, they were victims of a car break-in so we can rule out the keys from the investigation."