Firefighters have described blazes tearing through homes and buildings in London as “absolute hell” – with residents evacuated, people taken to hospital and a major incident declared.

As temperatures in the capital soared to more than 40C on Tuesday afternoon, “several significant” incidents occurred, with people urged not to have barbecues or bonfires due to the “unprecedented” challenges crews face.

Residents were evacuated from their homes in the village of Wennington, east London, on Tuesday afternoon, where black smoke billowed into the air, while flames destroyed buildings and ravaged nearby fields.

A firefighter at the scene, asked by the PA news agency what conditions were like, replied: “absolute hell”, while those affected by the blaze said it had been spreading “fast”.

Two people were also taken to hospital suffering smoke inhalation following a fire in Dagenham.

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

Sadiq Khan said LFB had received more than 1,600 calls for assistance by late Tuesday afternoon.

He also said people should not be having barbecues anywhere in London, including in parks and private gardens – as well as on patios and balconies.

Jonathan Smith, assistant commissioner at LFB, told Sky News many of the fires are spread over wide areas and began because the ground is “tinderbox dry”.

He continued: “So even a small fire will develop very, very quickly if it’s not tackled effectively and efficiently in its early stages.

“We would also say to people that they don’t try and tackle fires themselves.

“The situation that you can see is extremely dynamic and these fires can develop very very quickly and we would not want to see members of the public exposing themselves to unnecessary risk.”

In Wennington, local residents could be seen being comforted, with hundreds of firefighters at the scene.

At least one home could be seen completely destroyed by the fire, while others appeared to be badly damaged.

Local resident Janet Hickey, 70, who has terminal pancreatic cancer, said she was forced to leave all her cancer drugs behind as they were evacuated.

She said: “I’ve got all my cancer drugs in the fridge.”

Her husband Patrick Hickey, 71, added: “We had to leave everything.

“We’re hoping against hope that our house is still there.”

A rescue centre has been set up at the Wennington Premier Inn for residents who have been evacuated.

Riminta Maceikaite, 38, and her son Nikas Janulevicius, 13, said their neighbours’ homes have burned down but as far as they can see from TV aerial shots, their house is still standing.

Ms Maceikaite said they were “very anxious“ about their home, adding: “When you look on a camera when it shows you from the sky it just freaks you out.”

Nikas said: “Our house is on the news and it’s the only house that hasn’t been burned so far.”

Lizzie Pittman, from Aveley in Essex, who works at some stables by the roundabout, said she was looking after five horses that were evacuated.

She said: “This is your worst nightmare. You can see it getting closer and closer. People are losing their houses but that’s bricks and mortar. People are losing their livestock.”

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 PA: “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.”

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.”

Mr Smith added that resources would be at the scene into the evening, warning that any spark not dealt with could risk “reignition”.

It was among the fires being tackled in London on Tuesday afternoon, which were:

– 30 fire engines dealing with a grass fire on Pea Lane in Upminster.

– 12 fire engines tackling a fire involving garden fencing and trees on Uxbridge Road in Pinner.

– 10 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.

Houses were evacuated in Dagenham following a “significant grassfire” which affected a number of buildings and left a man and woman in hospital due to smoke inhalation.

Liam Edwards, 25, from Bexley, a student at Oxford Brookes, speaking about a fire by the A2 in Dartford, said: “It was huge when we left it multiple fire engines I’d like to say it’s under control but who knows at this point ?

“I’ve lived in London and Kent all my life I’ve never seen anything like that before.”

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.”

London Mayor Sadiq Khan said on Twitter: “This is critical: @LondonFire is under immense pressure.”

He also said: “We simply can’t cope with the number of fires across our city directly attributable to the heatwave we’re experiencing, the dry grass, the way the fire spreads during the heatwave.”