London Mayor Sadiq Khan tweeted, "this is critical...please be safe".
London's firefighting authority declared a major incident in the British capital on Tuesday in response to the surge in fires amid a record-breaking heatwave in Britain and Europe.
The London Fire Brigade said it had deployed dozens of fire engines to several fires in and around the city, including thirty to a grass fire in east London. Television footage showed one blaze engulfing several homes.
"Firefighters are still meeting the needs of our communities, but declaring a major incident allows us to focus our resources," the brigade said.
Britain recorded its highest ever temperature, breaking 40C (104F) for the first time, as a heatwave gripping Europe intensified, scorching fields and damaging airport runways and train tracks.
"This is critical: @LondonFire is under immense pressure. Please be safe," London Mayor Sadiq Khan said on Twitter,
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