Firefighters urged people to stop using barbeques and clean up litter in outdoor areas to prevent fires in the hot weather – while more fires broke out.
At least eight hectares of land were damaged by the fire, which was declared a major incident on Sunday, at Hankley Common, near Farnham in Surrey, which was previously used to film part of the James Bond blockbuster Skyfall.
Crews are expected to remain at the scene through Monday.
And fire crews in London were also battling bushfires – with fires at Rummy Marsh in Enfield, Cranford Park in Hayes and Thamesmead all described as “weather-related”.
A mum-of-three is left with almost nothing after a fire destroyed her home on Britain’s hottest day
Eyewitness: UK heatwave: Surviving families count cost of ‘devastating’ Wennington house fires
Appealing to the public for help, the London Fire Brigade urged people to cancel all planned barbecues, remove litter, especially glass, from meadows and dispose of cigarettes properly.
The service tweeted: “Please help us prevent further fires by canceling all planned barbecues, removing litter, especially glass from meadows and disposing of cigarettes properly. Our firefighters and control officers do a fantastic job in challenging conditions. Your cooperation will help us a lot.”
Surrey Fire Service attended the call. It said: “Talk to young relatives about outdoor safety, pack a picnic instead of a barbecue, dispose of cigarettes and litter properly.”
Temperatures in southeast England reached 29 degrees Celsius (84 degrees Fahrenheit) on Sunday, according to the Met Office.
Images of blackened ground were tweeted by the fire service after a 20-hectare grass fire at Remmy Marsh in Enfield was brought under control.
Around 70 firefighters were sent to a grass fire in Cranford Park, Hayes, which burnt around five hectares of grass and brush and sent smoke across west London.
Big Jet TV, which provides live commentary on planes landing at Heathrow, said visibility at the airport was reduced and shared a photo of the runway covered in smoke from a nearby fire.
Meanwhile in Thamesmead, around 65 firefighters and a fire boat tackled a grass fire on Defense Close.
Great Britain is experiencing a the heat, with a record high of 40.3C in Coningsby, Lincolnshire, on Tuesday.
Why a 40C day in the UK is deadlier than a 40C day elsewhere
That day was the busiest day for the fire service since the Second World War due to the extreme temperatures, with crews suffering 1,146 incidents on that day alone.