A 16-year-old boy has been arrested by detectives investigating the fatal stabbing of a teenager at a packed London train station.

Louis Johnson was stabbed to death in a violent attack that lasted 40 seconds on Monday afternoon.

The arrested boy, also 16, was detained in Balham in connection with the murder of Mr Johnson, but details of the arrested boy’s alleged involvement in the incident have not yet been disclosed.

British Transport Police said Mr Johnson came into East Croydon station at around 4.30pm through the Ruskin Square ticket barrier, and was attacked minutes later.

While he was on the overbridge in the station he met someone who immediately pulled out a knife and stabbed him, the BTP said.

Emergency services were called at around 4.45pm, but despite the efforts of medics, including an air ambulance team, he died.