Police are investigating a racially motivated attack which happened in July.
The driver of an X5 coach from Cambridge was abused by a man travelling to MK between 4.35pm and 4.45pm on July 14 last year.
The victim did not sustain any injuries.
Officers want to speak to the man shown in the CCTV image.
If you recognise the man pictured, or have any information about the incident, call 101.
If you do not want to speak directly to the police you can contact Crimestoppers anonymously on 0800 555 111.
No personal details are taken, information is not traced or recorded and you will not go to court.