The incident happened on Sunday, June 24, where a 30-year-old man was knocked unconscious in Cleveland Street, Chorley after he was punched by another man.
A police spokesman said: "We got the call at 4.10am on June 24 saying there was an assault in Cleveland Street.
"A 30-year-old man was approached by another man following a night out.
"There was an altercation and the victim was punched in the face and knocked unconscious."
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Chorley Police are now looking to talk to the three men pictured in the above still from a local CCTV camera.
PC Rik Nicol of Chorley Police said: "I am appealing for information relating to nasty assault whereby the victim was knocked unconscious and received facial injuries.
"Do you know the three males within this footage?
If you do please contact me via email [email protected]
If you wish to remain anonymous, you can contact me via Crimestoppers on 0800 555 111 quote crime number SC1805758."