A large fire which sent up huge plumes of black smoke in north London started at a cannabis factory, police believe.
At its height about 100 firefighters tackled the blaze at a number of factory units in Garman Road, Tottenham, on Thursday.
People living nearby have been urged to keep doors and windows closed due to the large amount of smoke.
The Met said it believes the fire began at a unit being used to grow cannabis before spreading to others.
The London Fire Brigade said a large part of the roof of a range of units was destroyed, to the rear of where the fire took hold.
It was called at 00:10 BST and the fire was brought under control by 12:24 BST.
Station Manager Lee Sandy said: "Due to structural damage it has been difficult for crews to gain access to the building.
"Crews were on scene throughout the night tackling the blaze and now have the fire under control and have stopped it spreading any further."
He added: "There is a lot of smoke and we are reminding people to keep windows shut in the local area."
The large plume of smoke could be seen across London.
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We continue to tackle the large warehouse fire in #Tottenham. If you’re in the local area please close your doors & windows as there is heavy black smoke coming from the blaze https://t.co/SZ71NPVWrm pic.twitter.com/VfEOobyYD6— London Fire Brigade (@LondonFire) May 23, 2019