A 35-year-old man was assaulted last Saturday in the toilets of The Dog and Gun pub, in Banbury.
The assault happened between 11pm and 11.30pm on Saturday in the North Bar Street pub.
The 35-year-old man was taken to hospital with head injuries and has since been discharged.
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Thames Valley Police have arrested a 29-year-old man from Banbury on suspicion of assault and has been bailed until December 7.
Police have now put out an appeal for witnesses following the assault.
Investigating officer, PC Peter Butt-Gow, of Banbury police station, said: “I am appealing for witnesses to this incident, during which this man sustained head injuries requiring hospital treatment.
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“If anyone was in The Dog and Gun public house at around the same time and saw anything relating to this incident, please get in touch with police."
Police ask for anyone with information to call 101, quoting 43190350737.
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