Investigators suspect a huge wildfire on a Cumbrian fell could have been started deliberately – while the countryside manager who raised the alarm has praised the rapid response of firefighters.

More than 40 firefighters and mountain rescuers from across the county spent more than five hours tackling the Borrowdale blaze.

A police helicopter from Newcastle was also sent to the scene while the National Trust had a second helicopter on standby ready to douse the flames from the air.

A fire chief said that firefighters and mountain rescuers were met with a wall of flames up to a mile wide when they scaled the moorland.

Many walked up wearing specialist backpacks and equipment used to tackle wildfires. Others were taken up by a farmer on his quad bike.

The blaze spread across 10,000 square metres of grass and gorse – around the size of 10 football pitches – on Grange Fell, between Watendlath and Rosthwaite.

Twenty-six firefighters, all trained in fighting wildfires, from five stations – Keswick, Appleby, Whitehaven, Ambleside and Windermere – were involved.

Seventeen members of Keswick Mountain Rescue Team provided support, offering local knowledge, navigation, logistics and welfare, as well as an emergency backup in the event of any injuries.

A mountain rescue volunteer was also airlifted by the police helicopter to help plot and track the fire.

A command centre was set up at the Keswick Mountain Rescue Team base as the situation unfolded on Wednesday afternoon, co-ordinated by senior fire officer Adrian Holme.

The land is owned by the National Trust. Penny Webb, the trust’s countryside manager for the north Lakes, called 999.

Mrs Webb, who was assessing the full scale of the damage yesterday, said: “They were absolute stars and I can’t thank everyone enough for their quick reaction.

“It was me that called 999 and so I know exactly how quick the response was. I’d taken a call in our office from one of our tenants who said there was a fell fire.

“I’ve got to thank Stanley Jackson from Nook Farm in Rosthwaite too. He took some of them up on his quad bike because access and the terrain was so difficult.”

The National Trust lined up a helicopter to help if crews could not bring the blaze under control.

“A helicopter would cost around £1,000 an hour in an operation like this. If the fire had continued and we had to call it in, we as a charity would have had to foot the bill. We’re very grateful to the ground crews.”

Mr Holme, Carlisle and Eden operational commander for Cumbria Fire and Resuce Service and an advanced wildfire manager, said: “The terrain was very challenging and the scene of the fire was 20 minutes from the nearest road.

“It was very hard to reach and the crews were all specially trained and fully kitted out in the right equipment. It was very physically demanding for all involved, both the crews and the mountain rescuers who provided fantastic support.”

He added: “The cause is still under investigation but we can not rule out that it was a deliberate fire.”

Emergency services were stood down at around 7.30pm.