Ten fire engines and around 70 firefighters tackled a grass fire on Wanstead Flats, near Capel Road in Manor Park.
Multiple seats of fire affected an area of approximately 14 acres of grassland. There were no reports of any injuries.
Station Commander Darren McTernan, who was at the scene, said: "Crews have been working hard, in hot, arduous conditions to bring the fire under control.
"Capel Road, Aldersbrook Road and Forest Road are currently closed and we advise people to avoid the area where possible, as we are likely to be on scene for a number of hours this afternoon.
"We deployed a wildfire response vehicle to the incident and also had Wildfire Support Officers at the scene, to support the Incident Commander. They also worked closely with partners from City of London Corporation."
The Brigade's wildfire response vehicles provide off-road capability enabling the transportation of additional equipment closer to fires on open ground. Each vehicle carries approximately 475 litres of water, a backpack blower, ear defenders, beaters and misting lance technology, which allows firefighters to pump water and drive, enabling them to tackle grass fires more quickly and safely. The Brigade is currently trialling four wildfire response vehicles across the capital.
The Brigade's Control Officers took the first of more than 20 calls to the fire at 1249 and mobilised crews from East Ham, Stratford, Leyton, Barking and surrounding fire stations to the scene. The fire was under control by 1513.
A London Fire Brigade spokesperson added: “During this latest heatwave, it is important everyone acts responsibly to prevent fires from occurring. As the weather has been so dry, it only takes a few sparks to lead to a fire spreading rapidly. In London, this is can be dangerous because so many of our green spaces lie close to homes and other properties.
“If you’re heading out, please don’t take a disposable BBQ with you. They can retain heat for several hours after use and are banned by local authorities from many of London's parks. Also make sure you are discarding of cigarettes properly and take rubbish home with you if no bins are available.
“At home, make sure your BBQ is positioned away from flammable items like fences, sheds, decking and trees and please don’t have any type of BBQ on your balcony. We’re also strongly advising people to avoid burning any waste in this type of weather and to not have bonfires, particularly in their gardens.”