At just before 8pm on 19 November, the victim was on the station’s concourse dressed as Pudsey Bear collecting for charity.
A man then approached the victim from behind and kicked him in the back while recording it on his phone.
Officers are keen to speak to the man in the CCTV image as he may have information that could assist with their investigation.
If you recognise him, or have any information, you can contact BTP by texting 61016 or calling 0800 40 50 40 quoting reference 336 of 19/11/21.
Alternatively, you can call Crimestoppers anonymously on 0800 555 111