Around 70 firefighters and ten fire engines tackled a grass fire on Ramnsey marsh in Enfield, North London on Saturday.
The London Fire Brigade told people to avoid the area and said they had received 55 calls about the blaze.
Mayor of London Sadiq Khan responded to news of the fire, saying: “The fire on Romney Marsh, Enfield, is producing a lot of smoke across the area including the M25 between junctions 25 and 26 - avoid the area if possible.”
An area of grassland measuring around 900m by 600m was alight, according to the emergency services.
Fire crews got the blaze under control at around 7:30pm.
“This summer has seen an unprecedented long, dry spell with high temperatures so the grass in London is tinderbox dry and the smallest of sparks can start a blaze which could cause devastation,” a spokesperson for the fire brigade said.
They continued: “Despite our continued warning over the last few weeks, we know there are still people who are barbecuing in parks, dropping cigarettes out of car windows and leaving rubbish lying around.”
The cause of the fire is still unknown.