Crews are dealing with ‘significant incidents’ in Enfield, Hayes and Thamesmead.
Firefighters are tackling multiple weather-related blazes across London and have appealed to people to cancel all planned barbecues in a bid to prevent further outbreaks.
London Fire Brigade (LFB) said it was dealing with significant incidents in Enfield, Hayes and Thamesmead.
The fire service said it had dealt with more incidents on Sunday than it normally would in a 24-hour period.
Appealing to the public for help, LFB urged people to cancel all planned barbecues, remove rubbish, especially glass, from grassland and dispose of cigarettes properly.
The service tweeted: “London Fire Brigade is dealing with a number of weather related fires across the capital. We’re tackling significant incidents in #Enfield, #Hayes and #Thamesmead. Between midnight and 1700 we’ve attended more incidents than we would in a normal 24 hour period.
“Please help us prevent further fires by cancelling all planned BBQs, removing rubbish especially glass from grassland & disposing cigarettes correctly. Our firefighters & control officers are doing a fantastic job in challenging conditions. Your co-operation will help us greatly.”
Temperatures across the south-east of England reached 29C on Sunday, according to the Met Office.
Images of blackened ground were tweeted by the fire service after the Enfield grass fire at Rammey Marsh over an area of 20 hectares was brought under control.
Some 70 firefighters were sent to the grass fire in Cranford Park, Hayes, where around five hectares of grass and shrubland were alight and smoke spread across west London.
Meanwhile, dark smoke could be seen rising into the air in Thamesmead as fire engines, the fire boat and around 65 firefighters dealt with a grass fire on Defence Close.
The UK has been experiencing a heatwave with a record-breaking high of 40.3C, in Coningsby, Lincolnshire, on Tuesday.
That day the fire service saw its busiest day since the Second World War as a result of the extreme temperatures with crews attending 1,146 incidents on that day alone.