Officers are investigating a robbery which occurred on board a train in Kent.
They have released CCTV footage of those believed to be involved and are asking if anyone recognises them.
On the 11th August at 2:45pm, two men on board a train approaching Dartford station demanded the victims mobile phone.
When the victim tried to move away from the two men, they grabbed him by the neck and grappled him to the floor to make him unlock his phone.
Once this occurred, the two men ran off the train at Dartford station.
The man in the CCTV are believed to have information which will help the investigation.
Anyone who recognises the men or has any information regarding the incident should contact British Transport Police by texting 61016 or calling 0800 40 50 40 quoting reference 322 of 11 August.
Or people can call Crimestoppers on 0800 555 111.
As they ran off. Did one of the ticket gateline staff tried to stop them. Evil people are all over the place.