A 50-year-old man was punched in the face by a stranger after parking in a Bletchley supermarket.
The incident happened at 5.10pm on Tuesday (October 21) as the victim left his car outside the Tesco store in Melrose Avenue.
A slim white man approached him, pushed him, and then punched him in the face, leaving the victim with a cut lip.
The two men then had a verbal altercation, before the attacker drove away in a dark-coloured vehicle.
The offender is described as being aged between 30 and 40, wearing dark green trousers and a dark green jacket which possibly had writing on it.
Anyone with information should contact PC Sarah Nash via the Thames Valley Police Enquiry Centre on 101.
Alternatively call Crimestoppers, anonymously, on 0800 555 111 or online at www.crimestoppers-uk.org