A member of staff at Harold Wood Station, which lies on the London Underground's Elizabeth Line and the Great Eastern Main Line, called police just after 4.30am on Tuesday.

They reported someone had been badly hurt.

Police and ambulance crews went to the scene but the victim, whose gender has not been disclosed, was pronounced dead.

A man has been arrested and is in custody, British Transport Police (BTP) said.

Detective Chief Inspector Sam Blackburn said: "This act of unprovoked violence was despicable.

"The investigation remains in the early stages, and although we are satisfied that this was an isolated incident, the station will remain closed while we continue our enquiries."

Anyone with information about the attack has been urged to contact police.