London Fire Brigade (LFB) has declared a major incident due to “a huge surge” in blazes across the capital amid the 40C heat.

It comes after around 100 firefighters tackled a blaze in the village of Wennington, east London, on Tuesday afternoon, with television footage showing black smoke billowing into the air, with buildings and fields on fire.

The fire brigade said in a statement it is battling “several significant” incidents in the capital, as people have been urged not to have barbecues or bonfires due to the “unprecedented” challenges crews face.

London Mayor Sadiq Khan said LFB is under “immense pressure”.

LFB’s assistant commissioner for operational resilience and control, Patrick Goulbourne, said: “The brigade remains ready to respond to incidents.

“However, we want to ensure our resources are available for people who really need our help.

“If you see a fire smouldering, please don’t hesitate to call us.

“The sooner we know about a fire, the sooner we can bring it under control and prevent it from spreading further, reducing the need for us to mobilise additional resources.

“We are also strongly urging people not to have barbecues or bonfires today as the ground is incredibly dry, which means even the smallest sparks could cause a fire.

“Please take care during the heatwave as all emergency services are facing unprecedented challenges.”

Mr Khan said on Twitter: “London Fire Brigade has just declared a major incident in response to a huge surge in fires across the capital today.

“This is critical: @LondonFire is under immense pressure.

“Please be safe. I’m in touch with the Commissioner and will share updates when I have them.”

It came as temperatures in the city hit around 40C.

LFB said 15 fire engines and about 100 firefighters were called to Wennington just after 1pm.

At least one home appeared to be destroyed in the fire, while smoke covered a wide area.

Nearby resident, Lynn Sabberton, who said she was evacuated from her home with her partner who has a lung difficulty, told Sky News: “We thought it was one of the fields that caught alight over the back of us.

“But then a neighbour rang me and said, ‘oh no, it’s on the green, the green has caught fire’.

“I saw the black smoke and the helicopters came over and more police came into our neighbourhood and it was really spreading very fast.

“It just spread so quickly, I think the wind caused the fire to go our way towards the village.”

Freya Gutteridge, 23, from nearby Hornchurch, who works in marketing, told the PA news agency: “I noticed the fire in Wennington when I went to lunch at two and since then our whole office has just been watching – everywhere we look there’s a new one.

“We’re all really worried, the wind is strong and we’re seeing on the news that loads of houses are on fire and there isn’t enough fire engines.

“It’s crazy. Most of us in the office live really locally so we’re all worried about families’ houses at the moment.

“We know that if we were in any danger that we would be evacuated but there are petrol stations around and things like that so we’re more scared for everyone in the area.”

Nearby fields were seen to be scorched.

Witness Pierre L’Aimable told Sky News: “We were driving down the road and we just saw so much smoke, we could see it from Hornchurch just going into the air.

“We were going to visit one of my business partners and the fire was just immense.

“There was so much black smoke in the air, there were fire engines going past.”

He said people were being evacuated from their homes, while horses were being taken to safety from stables.

Train operator c2c Rail said the line between Ockendon and Upminster is closed until the end of the day due to the fire.

Thirty fire engines were also dealing with a grass fire in Pea Lane, Upminster.

The fires being tackled in London on Tuesday afternoon:

– Thirty fire engines dealing with a grass fire on Pea Lane in Upminster.
– Fifteen fire engines tackling a fire on The Green in Wennington.
– Twelve fire engines tackling a fire involving garden fencing and trees on Uxbridge Road in Pinner.
– Ten fire engines tackling a restaurant fire on Green Lanes in Southgate.
– Eight fire engines tackling a grass fire on Oaks Road in Croydon.
– Eight fire engines tackling a grass fire on Ballards Road in Dagenham.
– Eight fire engines tackling a fire on The Broadway in Wembley.
– Six fire engines tackling a grass fire on Sunningfields Crescent in Hendon.
– Four fire engines tackling a grass fire on Chapel View in Croydon.
– Four fire engines tackling a fire on Sidcup Road in Eltham.