POLICE are seeking public help to solve the mystery of a 140mph car convoy in Dumfries and Galloway.

Traffic police spotted the four speeding cars on the A74 (M) heading south.

The vehicles were doing more than 140mph when spotted between Johnstonebridge and Ecclefechan at around 12:15 on Sunday.

Officers were unable to stop the cars and it is not clear whether speed cameras would have captured them

The offending cars were a blue BMW M6, orange Nissan GTR, red Audi S5 and grey Porsche GT3.

Sgt Leigh McCulloch of the Trunk Roads Policing Group said: "These four cars were observed by officers travelling south and it is suspected that they were travelling in convoy.

"The speed of these vehicles was recorded as being more than double the legal limit for the motorway.

"Clearly speed to this level on a public road is totally inappropriate and I am appealing to anyone who may have been on the A74(M) to call us if they can help us identify these vehicles, or indeed on any other roads south of Ecclefechan in the lower Annandale area during early Sunday afternoon. "

Any motorists with dash cam footage have been asked to come forward.