Heathrow airport was cut off from all train connections on Saturday morning after a burst water main caused signalling problems.

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.

Both affected trains have now reopened, with delays of up to 15 minutes and cancellations on the Heathrow Express.

There is good service on the Elizabeth Line, Transport for London (TfL) said.

However there is still no service between Acton Town and all Heathrow terminals on the Piccadilly Line because of the planned works. Rail replacement buses are in place for these services.

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

At 12.20pm Heathrow airport’s X account posted a statement which said: ‘Services are now starting to resume on the Elizabeth line and Heathrow Express.

‘Please allow extra time when travelling due to the earlier incident. We apologise for any inconvenience caused.’

Airport-bound travellers waiting to board the Heathrow Express last year (file pic)

The Heathrow Express opened in 1998, running between the airport and London Paddington station with 150 trains a day.

Around 17,000 passengers take the journey, which takes 15 minutes to terminals two and three and 21 minutes to terminal five, each day.

It said disruption following the signalling problems could continue for the rest of the day. 

Heathrow is the UK’s busiest airport, with a record 84million passengers passing through last year.