A man 'growled' before punching his victim in the face at Newcastle's Central Station.
The incident occurred just before 9pm on May 13 in the Central Station's short stay car park, where a man is alleged to have growled, then punched his victim in the face causing him to fall to the floor.
The victim suffered a fractured collar bone and bruising to his body as a result of the attack.
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Officers from the British Transport Police have issued a picture of a man from CCTV images, who they believe may have information which could help their investigation into the serious assault.
Anyone who recognises him or has any information relating to the incident is encouraged to contact BTP by texting 61016 or by calling 0800 40 50 40 quoting reference 544 of May 13. Alternatively, Crimestoppers can be contacted anonymously on 0800 555 111.