A firefighter has described a moorland blaze as the largest he has seen in his 31-year career, as he praised colleagues for their “tireless” work to get it under control.

A major incident was declared when the fire broke out on Langdale Moor, near the ballistic missile early warning base at RAF Fylingdales, on Monday 11 August, as it reached about 1.9 to 3sq miles (5 to 8sq km).

Crews are expected to remain at the site for several more weeks and have been putting in firebreaks to stop it spreading further, despite the blaze almost being under control.

North Yorkshire Fire and Rescue group manager Andy Creasey said that workers are now trying to tackle an invisible fire burning under the ground.

He said: “I’ve worked for this fire service for 31 years and in that time, this is the largest moorland fire I’ve ever attended in my career.

“We do have an issue when the fire is burning into the peat soil, as when it’s on the surface it can jump and can go over into the heather and the moorland across the top of the road.

“But we’ve got the peat underneath the tracks that we’ve got in place, it can actually burn underneath the tracks and come out the other side as well, so our firebreaks are purposely put in to try and prevent that from happening.”

The area where the fire spread was used as a firing range decades ago and so buried emissions have now been exploding.

The fire crews have been working with the Ministry of Defence to ensure the devices are detonated safely.

Mr Creasey said crews have been working nonstop for nearly two weeks to get it under control.

“The people who are here are just here to do their job, they understand the nature of the work they are doing and they are working tirelessly to try to prevent any further spread from this fire,” he added.