A man was taken to hospital with serious head injuries after being assaulted in Leatherhead.
The incident took place at about 1.15am on Saturday, April 7, as the man, in his 30s, was walking along Leatherhead High Street, opposite the Subway sandwich shop.
Ambulance crews attended the scene and the victim was taken to hospital for treatment.
Detective sergeant Vicki Morris, of Epsom CID, said: "It is thought both the victim and the offender had been out socialising before the incident took place and although it is believed they are not known to one another they may have spoken to each other earlier in the evening.
"The town centre would have been busy around this time and I would appeal to anyone with information to contact officers as a matter of urgency."
Police said they are looking for a white man with dark hair.
Anyone with information should call the police on 101 quoting reference MV/12/1421 or Crimestoppers on 0800 555 111.
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