An elderly man was forced to have hip replacement surgery after being violently pushed to the floor as he attempted to get on a bus.
It happened as the 70-year-old man was trying to board the number 76 bus in Piccadilly Gardens just before 4pm on 1 February 2013.
The man was queuing for the Oldham-bound bus with his wife when a man with a young girl, aged either four or five-years-old, pushed in front of them.
The man challenged the offender about his queue-jumping, at which point he was violently pushed in the chest causing him to fall to the floor. The offender and the young girl then walked off towards Lever Street.
As a result, the victim had to undergo hip replacement surgery as he severely fractured his hip, and he is still recovering in hospital.
The offender was seen walking away from the scene towards Lever Street and finally onto Oldham Road. He was with the little girl all the way and the pair then met up with another woman outside the Royal Mail sorting office on Oldham Road.
Police have now released two CCTV stills of the offender - including one of him, the young girl and the woman walking along Oldham Road.
Officers are appealing to anyone who recognises the offender himself or who knows who it might be from the very distinctive blue flowery raincoat the young girl was wearing to come forward. It is believed the offender may live in the Collyhurst area as there was a later sighting of him near to Livesley Street.
He is described as being black, of a slim build, in his mid 20s and about 5ft 6in to 5ft 7in tall. He was wearing a black jacket. The young girl with the blue jacket was also black, as was the woman the pair later met up with.
Detective Constable Paul Wilde said: "This was a totally needless, shocking attack on an elderly man who, as a consequence, has suffered a life-changing injury. He has been in good health all his life and now, after one moment of madness, he is still in hospital recovering from hip replacement surgery.
"What makes this even more galling is that the victim and his wife were simply minding their own business when this offender decided to barge in front of them. Quite rightly, the victim confronted him and was violently pushed over for his troubles.
"It is an appalling incident and we need to find the man responsible.
"I would urge people to look very carefully at the CCTV images we have released. If you think you recognise this man, or perhaps recognise the family from the distinctive coat the young girl was wearing, we really need to hear from you.
"I would also like to make a direct appeal to the offender himself. As a result of your actions, a 70-year-old man has suffered a very severe hip injury and is in hospital. Please, do the right thing and come forward."
Anyone with information should call police on 0161 856 3120 or the independent charity Crimestoppers, anonymously, on 0800 555 111.