British Transport Police has released a CCTV image of a man it is tracing after a commuter was allegedly pushed on to the Northern line at Kentish Town Underground station and struck by a train.
The incident happened at about 11.45am on 2 December, with the man who suffered serious injuries receiving treatment at the scene before being taken to a local hospital. The suspect was seen fleeing the scene before boarding a Tube in the direction of High Barnet.
Detective superintendent Gary Richardson said: "We have received reports from witnesses that the man was pushed in front of a train and we are currently treating this as an attempted murder. We are now issuing images of a man we want to speak to in connection with the incident and appealing for any witnesses to come forward.
"He was at the station at the time and we believe he will be able to help our enquiries. He is described as black, clean shaven, aged 20 to 30, around 5ft 11in, stocky build, with short hair.
"After the incident, the man pictured ran to the northbound platform where he boarded a Tube in the direction of High Barnet. If you know who he is, please contact us immediately. Anyone with any information please call us on 0800 40 50 40 or text 61016 quoting reference B18 of 02/12/15."
Kentish Town station remains closed following the attack but there is a good service on the rest of the Northern line.