The hot weather has melted the flight line at a key RAF base in Lincolnshire, impacting flying training for pilots, Sky News understands.

An RAF spokesperson, however, insisted that flying training had not been affected.

An informed source told Sky News that officials at RAF Cranwell had been “dragging tar around” on their boots and even on the wheels of the Phenom and Prefect training aircraft since the start of the summer as the tarmac on the ground softened in the sunshine.

The situation at the flight line – the area where aircraft are serviced, parked and prepared for use – became so grave in the heat on Monday that flights were halted, according to the source.

Temperatures soared across the UK, hitting 32C in London, with the Met Office warning it will only become hotter.

Analysis: Britain’s heating climate will become increasingly uncomfortable – and deadly for some

The flight line is also where aviators board their aircraft and taxi towards the runway.

“Our aircraft flight line has melted in the heat, so all flying at Cranwell has been stopped,” the source said.

“Obviously all the trainees are f***** off as it’s just a s*** show.”

Asked about the claim that flying training on aircraft at the base had been halted because of the flight line melting in the heat, the RAF spokesperson said: “As a precautionary measure, the main aircraft service area at RAF Cranwell is currently unavailable for routine use.

“Flying training is not affected and will continue by using alternative service areas.”

It was not immediately clear which alternative areas, though possibly RAF Barkston Heath, about a 10-mile drive from Cranwell.

Adding to the pressure, a number of airfields have been closed in recent years as part of cost-cutting, limiting the availability of viable alternatives.

The informed source insisted: “All flying today [Monday] and tomorrow [from RAF Cranwell] is cancelled.”

The source said around 60 students doing elementary flying training and multi-engine training courses have been impacted by the disruption.

It is understood that an investigation has been launched to find out why the main flight line has suffered problems. Extreme heat is thought to have been a contributory factor.