Burned out cars are pictured in a charred section of a car park, following a fire at London's Luton Airport.

Up to 40,000 passengers have been affected by flight cancellations after a large fire broke out at one of London’s Luton Airport’s car parks. The airport has now suspended all flights until at least 3pm, as firefighters remain at the site of blaze that broke out just before 9pm, according to the Independent.

The newly-built car park building at the airport’s Terminal 2 has partially collapsed, the Bedfordshire Fire and Rescue Service said. It was not known if any passengers were trapped on the tarmac, inside the airport or in the Terminal 2 car park.

The fire service said it was called to the incident just before 9pm and over 10 fire engines were at the scene. It added that 80 per cent of one of the car park’s third floors was impacted by the blaze. Up to 1,200 vehicles may have been in the car park at the time of the fire and subsequently damaged.

Luton is Britain's fifth busiest airport after Heathrow, Gatwick, Stansted and Manchester, and it had 13.3 million passengers in 2022, according to the Civil Aviation Authority. There were no fatalities in the fire, reported to emergency services late on Tuesday.

Huge flames swept through the structure located a short distance from the airport terminal, says Reuters. Four firefighters and a member of airport staff were taken to hospital to be treated for mild smoke inhalation but have since been discharged. "Our priority remains supporting the emergency services and the safety of our passengers and staff.

Therefore, we have now taken the decision to suspend all flights until 3pm on Wednesday," the airport said in a post on X. The suspension had earlier been set to run until 1100 GMT. The cause of the fire appeared to be accidental, local fire chief Andrew Hopkinson told reporters. "We've got no intelligence to suggest it's anything other than an accidental fire that started in one of the vehicles," he said. Up to 1,200 cars could have been in the car park at the time, the fire department said.

"One half of the structure was fully involved in fire and the building suffered a significant structural collapse," it said. An investigation would be undertaken to determine the cause of the fire, it said.

The airport handles around 40,000 passengers a day in October on several hundred mostly short-haul European flights, CAA data shows. Britain's easyJet said it was "doing all possible to minimise the impact on our customers, providing those on cancelled flights with options to re-book or receive a refund, as well as providing hotel accommodation and meals where required". Ryanair and Wizz Air said affected passengers would be contacted as soon as possible.