A BMW was involved in a crash on the M1 near Junction 6a for the M25 earlier this month – and now police have launched an appeal for witnesses to come forward.

The black BMW 5 Series was involved in the collision on the southbound carriageway of the M1 - near the M25 interchange, north of Watford, on Sunday, December 8, at about 1.40am.

PC Emma Alston said: "We are appealing for witnesses as this is a very busy stretch of road. If you were driving in the area at the time, and witnessed the collision or drove past the scene after it happened, please get in contact.

"Alternatively, if you were driving near Junction 6a around the time specified and have a dash cam fitted to your vehicle, please review the footage and send us anything that you think could be of use.

"We also believe that one witness in particular, a woman who was driving a white car who stopped to help one of the motorists, could have key information which could assist our investigation. If you were that motorist, or you know who she is, please get in touch with us as soon as possible."

Anyone with information is asked to contact PC Alston directly via email at emma.alston@herts.pnn.police.uk.

You can also report information online, speak to an operator in the force communications room via online web chat or call our non-emergency number 101 quoting ISR 87 of 8 December. If a crime is in progress or someone's life is in danger, call 999 immediately.

Alternatively you can call Crimestoppers anonymously on 0800 555 111 or report information online.