A GRASS fire closed a runway at the UK’s biggest airport today.

Heathrow’s southerly runway was closed as the blaze took hold, sparking chaos and flight delays.

Smoke plume rising from a distant section of an airport runway.A fire has closed one of the runways at Heathrow Airport Smoke rises from an airport runway after a plane crash, with a fire truck visible in the distance.Firefighters and emergency services raced to scene of the inferno

Firefighters and emergency services raced to the scene of the inferno adjacent to the tarmac, where planes were waiting to take-ff.

A Heathrow Airport spokesperson told The Sun: “Earlier our teams responded to a grass fire adjacent to the southern runway.

“The fire was extinguished quickly, both runways are operational and flights continue to arrive and depart from the airport.

“We apologise for any disruption caused while emergency services completed their safety checks, but this was essential to ensure the safety of our passengers and colleagues.”

Heathrow Runways posted on social media: “Grass area fire abeam runway 27L has closed the runway, we are now single runway ops on 27R UFN.”

Flyers faced with disruption took to social media, one wrote: “The one time I fly from Heathrow, it’s down to 1 runway and the trains down are disrupted by swans on the tracks. Can’t make it up.”

A second added: “Fun morning at Airport with a grass fire being dealt with beside runway 27L.

“Despite the recent rain, the grass is still like a tinderbox.”

A third said: “Looks largely contained. Water cannons had been brought out on both sides of the grassy verge that was on fire.”

This comes after yesterday due to a “technical issue”.

It is understood a plane was stuck on the runway and was seen surrounded by fire trucks.

Many flights were forced to divert to other airports in the area.

Last month a grass fire again beside the runway caused chaos for passengers at Heathrow.

London Fire Brigade were called to the scene and battled the blaze which was said to have caused one hectare of grassland.

Many passengers had their flights delayed by hours as the number of planes able to take-off and land was reduced.