A driver had his jaw and eye socket broken after being robbed when his car was pulled over by a fake police car after a motorway collision.
The incident happened last Sunday evening at about 9.15pm, Thames Valley police said.
The victim, a man in his 30s, was travelling south along the M40 between High Wycombe and Beaconsfield in Buckinghamshire when his car collided with another vehicle.
Another car with flashing blue lights motioned the driver to pull over into a layby on the A355. A group of men then grabbed the man from his car and stole his phone, wallet and keys while beating him so severely that he needed treatment in hospital. The men are believed to have pulled up in a red Nissan and a dark-coloured Volvo.
PC Mollie Dugmore, based at Aylesbury police station, said: “Impersonating a police officer is an offence that we will not tolerate, and we are appealing for information following this incident.
“We are asking anyone with information to please call 101 quoting reference 43240506514.
“Additionally, we ask anyone with mobile phone, CCTV or dashcam footage from the M40 or the surrounding areas at around 9.10pm to get in touch with the force in case it has captured something which may assist this investigation.
“If you do not wish to speak to police you can contact the independent charity Crimestoppers on 0800 555 111.”