London Fire Brigade has urged people to help prevent blazes in the continued hot weather after dealing with its biggest ever grass fire.

One hundred firefighters remained at the scene of the wildfire at Wanstead Flats, an area of open grassland in Epping Forest, north-east London, on Monday.

At its peak an area the size of 100 football pitches was alight, the fire brigade said of the blaze, which broke out on Sunday afternoon and has since been brought under control.

The service, which said the incident was the largest grass fire in its history, has issued an urgent safety warning to the public, as the UK’s hot spell continues.

London Fire Commissioner, Dany Cotton, said grass fires can spread like lightning and added that they are “praying for rain”.

She said: “We are calling on the public to take steps to prevent grass fires: don’t drop cigarettes or matches on dry ground or out of car windows; don’t have barbecues on dry grass or parks and don’t leave glass bottles out as they can concentrate the sun’s rays and start a blaze.”

On Saturday five hectares of grass and scrubland caught light in Feltham, close to Heathrow Airport, and burned for nearly five hours before being brought under control.

Elsewhere crews attended grass fires in Essex, Woodford Green and Richmond at the weekend.

The fire brigade said there had been 821 grass fires attended in London so far this year, and noted that big grass fires in an urban area like the capital is “extremely unusual”.

Meanwhile, firefighters are still working on moorland in the north of England, after huge fires broke out last month.

Greater Manchester Fire said on Friday they would remain on site at Tameside, Bolton and Denshaw “until firefighters are confident that there is no chance the fires can reignite”.

Fires on Saddleworth Moor and Winter Hill, near Bolton, were declared as major incidents as flames spread over dry ground in the heat, but Thursday saw rain fall in the North West for the first time since the blazes began.