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

Louis Johnson was stabbed to death in a violent attack at East Croydon 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 his 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 at the scene.

His death was likely due to be a postcode wards, according to friends who said Louis was seen as an “opportunity” having lived in Tooting and Lewisham before moving to South Norwood.

Close friends Mia and Ashanti, who knew Louis since beginning secondary school aged 11, laid flowers at the scene on Tuesday.

Mia, 16, from Lewisham, said: "“The person had a machete, clearly knowing they were targeting Louis.

“The police think they are doing everything they can to stop knife crime but it is so easy to buy a machete online within five seconds and click and collect.

“Louis would never approach someone he was unsure of. If he knew something was going to happen, he would take himself out of the situation. He was set up.

“It was probably just postcode wars and it is that stupid. We are living in 2020 and still there are people who carry a knife and trying to prove they are a big bad person."