An area of grassland measuring around 900m by 600m is ablaze and 10 fire engines were sent to the scene at Rammey Marsh in Enfield following a call at 12.59pm. The London Fire Brigade (LFB) said the flames were producing heavy smoke over the M25 between junctions 25 and 26. The cause is yet to be ascertained. The LFB reiterated its message to the public not to barbecue outdoors and dispose of litter and cigarettes properly to prevent fires starting, with temperatures reaching 34 degrees in southern England. At around 6pm, the LFB tweeted that “firefighters continue to work in hot and difficult conditions at the scene of the #RammeyMarsh grass fire”. A spokesman said: “This summer has seen an unprecedentedly long drought with high temperatures, so the grass in London is dry and the smallest of sparks can start a fire that could cause disaster. “Despite our continued warnings over the past few weeks, we know there are still people having barbecues in parks, throwing cigarettes out of car windows and leaving litter around. “We are asking Londoners to help us protect the city we all love by doing what you can to prevent further grass fires. Do not barbecue in open spaces or balconies, dispose of your rubbish safely and properly extinguish your cigarettes.’ Fire crews from Chingford, Hendon, Enfield, Southgate and surrounding fire stations are at the scene. On Thursday, three hectares of grass, shrubs and bushes were destroyed by a fire in Rainham, east London. It was the second time in two days that the meadow there had caught fire.