Around 70 firefighters are tackling a large blaze on Rammey Marsh in Enfield as temperatures soar to almost 35C in London.
Grass in the capital is “tinderbox dry” and “the smallest of sparks can start a blaze which could cause devastation”, the London Fire Brigade warns.
The fire is producing a lot of smoke over the M25 between junctions 25 and 26.
A London Fire Brigade spokesperson said: “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.
“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.
“We are asking Londoners to help us protect the city we all love by doing everything you can to prevent further grass fires. Please don’t barbecue in open spaces or balconies, throw your rubbish away safely and put your cigarettes out properly.”
The Brigade was called just before 1pm. Fire crews from Chingford, Hendon, Enfield, Southgate and surrounding fire stations are still at the scene.
The cause of the fire is not known at this time.
The brigade receid 55 calls about the blaze.