Heathrow has told passengers not to drive to the airport as flooding, caused by a burst main, hit access to Terminals 2 and 3.  

Flyers had been told to travel via train, as roads around Terminals 2 and 3 were closed, and allow extra time for their journeys. 

The airport 'strongly advised' passengers to arrive on Heathrow Express, Elizabeth line and Piccadilly line services instead. 

Passengers were also told not to park at Terminals 2 and 3. Instead they were advised to park at Terminals 4 or 5 before transferring. 

The flooding, caused by a burst main beneath beneath Inner Ring Road West, has continued to cause disruption in the central terminal area (CTA).

This refers to an area including Terminals 2 and 3, as well as a number of other buildings, connected by a network of roads. 

The main leak occurred beneath a road in this area. It is understood that there is no flooding within either terminal, and flights have not been disrupted. 

Heathrow said all roads have now been reopened, with the airport 'continuing to operate as normal'.  

In an update, the airport said: 'Following earlier flooding in the central terminal area impacting access to Terminals 2 and 3, all roads have now reopened and the airport continues to operate as normal. 

'We apologise for any inconvenience caused and we thank passengers for following the advisories we had put in place while our teams worked to resolve the situation as quickly as possible.'  

In a previous statement, Heathrow said: 'Flooding in the central terminal area has resulted in on-going road closures restricting access to Terminals 2 and 3.

'Passengers travelling to or from either of these terminals today must not travel by road.'

'Any passengers that must travel by car must use Park and Ride, head to Terminals 4 or 5 and take free rail services from there, or change at local rail stations. Please allow extra time for your journeys.' 

The airport added: 'Our teams are working to resolve the situation as quickly as possible, we apologise for any disruption caused.' 

Virgin Atlantic, which operates from Terminal 3, has advised customers to travel by public transport, adding that all its flights are currently running on time. 

An airline spokesman told the Mail: 'We're aware of road closures at Heathrow Airport due to flooding and are advising customers to either travel by public transport or use the park and ride facilities. 

'All our flights are currently operating as scheduled and customers can check the status of their flights on virginatlantic.com for the latest information.'

British Airways also said its flights are operating as usual. 

A spokesman for Heathrow Airport said: 'Flooding in the central terminal area has resulted in on-going road closures restricting access to Terminals 2 and 3. 

'Passengers travelling to or from either of these terminals today must not travel by road.

'Passengers are strongly advised to use Heathrow Express, Elizabeth Line and Piccadilly Line rail services where possible.

'Any passengers that must travel by car must use Park and Ride, head to Terminals 4 or 5 and take free rail services from there, or change at local rail stations.

'Please allow extra time for your journey. Our teams are working to resolve the situation as quickly as possible, we apologise for any disruption caused.'

It comes after a grass fire forced one of Heathrow's runways to close earlier this month. 

Runway 27L was closed for around an hour on August 6 while the airport's fire service battled the blaze.

Witnesses said crew from four fire engines 'quickly brought the blaze under control'.

The closure happened at peak time for the airport, which normally has two operational runways. 

The reduced capacity meant takeoffs and landings were delayed, with several arriving flights diverted to other English airports.

In May, a burst water main caused flooding at Terminals 2 and 3, suspending all trains to and from the airport. 

Heathrow was left cut off from all rail connections after a burst water main caused signalling problems on May 30. 

The Heathrow Express and Elizabeth line saw no service for much of the morning while the Piccadilly line was cut off from the airport for planned engineering works. 

National Rail apologised for the 'major disruption' after it said a burst water main near the airport caused a 'fault with the signalling system'. 

The airport reported its busiest day of the year last month as 267,000 passengers travelled via Heathrow on July 19, with 7.85million people travelling through the hub across the entire month.