In Wennington, a massive grass fire broke out with footage showing fields and buildings engulfed in black smoke on the hottest day ever recorded in the UK. Some 15 fire crews and 100 firefighters are currently battling the blaze at the scene in the Essex village, emergency services said.
In a separate tweet, Mr Khan outlined how to prevent fires, including avoiding barbecuing on grass or balconies, leaving broken bottles or glass on grass, disposing of cigarettes safely and reporting fires as soon as they are seen.
An LFB spokesperson said: "Common causes of grass fires include carelessly discarded cigarettes or matches, as well as rubbish left lying around such as glass bottles, which can start flames by magnifying the sun's rays."Every one of us can help reduce the risk of fire and keep our communities clean, make sure rubbish is safely thrown away and cigarettes are always properly disposed of.
" One regional service said the number of open fires could have tripled this week, PA reported, while the Met Office warned that most of England were at exceptional risk.
News of the fire was quick to spread on social media.
Kent Fire and Rescue Service said in a statement: "Kent Fire and Rescue Service has been called to reports of a grass fire near Durrell Dene, in Joyce Green, Dartford.
"Nine fire engines and a height vehicle have been sent to the scene, where crews are working to extinguish the fire."
