The heatwave has led to the unusual sight of gritters being used in the summer.

They are normally deployed during cold snaps to stop road surfaces from freezing, but a number of councils are using the vehicles to spread crushed rock dust as temperatures soar.

Some roads have become so hot that they have started to melt and stick to tyres.

Crushed rock particles are being spread by councils to create a non-stick layer between roads and vehicles.

Local authorities in Cumbria, Lancashire, Doncaster and Hampshire are among those using gritters this week.

A spokesman for the Local Government Association said: “Snow and ice are the last thing on most people’s minds at the moment and I’m sure there’s been a lot of head-scratching if they’ve seen our gritters out on the roads in the height of summer.

“However, our gritting teams are once again playing a vital role in keeping the country’s roads safe for motorists.

“This proactive work helps reduce the potential damage high temperatures can inflict on our roads, so keeping them safe and limiting disruption.

“Councils will continue to monitor road temperatures and once the weather cools will begin carrying out repairs if needed.”

Keith Little, cabinet member for highways at Cumbria County Council, said: “If the bitumen becomes overheated, this could potentially lead to a loss of shape in the carriageway surface as well as affecting vehicles.

“We have deployed gritters to protect our roads from longer-term damage, and also avoiding damage to people’s vehicles.”

RAC spokesman Simon Williams said: “Many motorists could be forgiven for thinking the sight of gritters on the road in the summer is a mirage caused by the heat.

“But they should actually be relieved councils have taken action as road surfaces could easily suffer hard-to-repair long-term damage.

“And with many local roads already in a dire state from the harsh winter weather, this is the last thing drivers and their vehicles need.”

Motorists who find sticky tar on their vehicles are advised to wash it off with warm soapy water.