Highgate Station has just reopened after firefighters tackled a huge fire by the north London Tube stop.
Plumes of smoke can be seen billowing out for miles away after the blaze broke out at roughly 3pm on Tuesday.
London Fire Brigade said that a derelict outbuilding had caught fire.
There were no reports of any injuries.
A neighbour told the Standard: “I heard a dull thud. I was walking back to my flat when I saw smoke billowing into the sky.
“As I got closer the flames took hold. Someone said an outbuilding had been set on fire.
“There’s been lots of talk recently about teenagers hanging out in that area of Queens Wood near the station.”
An LFB spokesman added: “Six fire engines and around 40 firefighters are tackling a fire at a building on Archway Road in Hornsey.
“Half of the first floor of the derelict building is alight.
“The Brigade was called at 3.01pm and the crews are fighting to bring the fire under control. Fire crews from Hornsey, Kentish Town, Holloway, West Hampstead and Finchley are attending the scene.
“The cause of the fire is unknown at this time.”
Scotland Yard said they were in the early stages of an investigation and were assisting firefighters at the scene.
A British Transport Police spokesman said: “Officers were called to Highgate Underground station at 3pm today following reports of a fire.
“Officers are on scene supporting the London Fire Brigade as they work to extinguish the fire and establish the circumstances of how it started. The station is closed and passengers are advised to avoid the area.”
A London Ambulance Service spokesperson said: “We have sent a number of resources to the scene, including an ambulance crew, a medic in a fast response car, an incident response officer and members of our hazardous area response team (HART).
“The incident is ongoing and we are working with our emergency service colleagues.”
