Transport for London confirmed no Elizabeth Line services ran between Hayes and Harlington and Heathrow after flooding struck Heathrow Terminals 2 and 3.
The flooding caused a signal failure that brought train services to a halt, leaving passengers stranded during one of the busiest travel periods of the year.
The Heathrow Express was also hit by the disruption, with the operator confirming all services were suspended as engineers worked to resolve the issue.
Heathrow Express posted on X: “Due to a significant incident outside of our control, there are currently no Heathrow Express services running. We are actively working to resolve the issue as quickly as possible.”
Passengers travelling via the Piccadilly line also faced difficulties, with no services running to the airport due to separately planned engineering works.
Services on both the Elizabeth line and Heathrow Express have since begun to resume, though the airport warned passengers to allow extra time “due to the incident.”
Families travelling for the half-term weekend were among those caught up in the disruption, with many taking to social media to vent their frustrations at the delays.
One user on X said they were forced to take “two buses and a train” after finding the Elizabeth line flooded, while another was redirected from Paddington via Reading on a bus.
A further passenger urged others to seek taxis rather than rely on Transport for London replacement buses, warning of serious knock-on problems at the airport itself.
That user wrote: “Get a taxi. If you take a replacement bus as directed by Tfl you end up stranded at Heathrow Central bus station with NO internal transfer options. It’s full meltdown here.”
Heathrow is the busiest airport in both the UK and Europe, and only last year recorded its busiest-ever day, with more than a quarter of a million passengers passing through its four terminals on 1 August.