Police have confirmed a man stabbed to death on a Surrey train had been travelling with his 14-year-old son, as the suspected killer remains at large.

A huge manhunt remains in progress as officers hunt for the suspected murderer, who is reported to have stabbed the father during what has been described as a “vicious fight” aboard the 12.58pm service travelling from Guildford to Waterloo.

British Transport Police has warned members of the public not to approach the suspected killer, who officers believe left the train at Clandon station.

Superintendent Paul Langley said: "What we know at the moment is that the victim boarded the train at around 1pm at London Road station in Guildford, along with his 14-year-old son.

Surrey Comet:

Steve Parsons/PA Wire

"Traumatically, the victim's son would have been nearby when his father was fatally wounded. This would have been an horrific and hugely traumatic event to have witnessed and we are providing him with as much support as possible.

"We know that the suspect also boarded the service at London Road station, however at this time we do not believe they are known to each other."

The identity of the victim has not been confirmed, but police have said he is believed to be aged 51.

Superintendent Langley added: "We have a number of officers in the area working hard to trace the man responsible for this violent and deadly attack. We are working close with Surrey Police and the National Police Air Service who are helping us to locate him.

"The suspect is a black man, in his 20s to 30s, approximately 6ft tall and of slim build with a beard, believed to be dressed all in black with white trainers.

Surrey Comet:

Steve Parsons/PA Wire

"At this moment I would ask the public to please contact police urgently by calling 999 if they see anyone matching this description - please do not approach him."

The victim was said to have suffered "multiple stab wounds" and died at the scene of the attack, despite the best efforts of South East Coast Ambulance Service paramedics.

The suspect is believed to have left the station at Clandon and set off in the direction of Dedswell Drive.

The incident has caused seven hours of disruption on the South Western Rail-operated line, though all service has since been resumed.

Extra police will be posted to the rail network for the remainder of Friday and Saturday to reassure members of the public and staff.