Eurostar said services through the Channel tunnel would resume on Sunday but there were warnings of further delays and busy stations.
“Unprecedented” flooding was brought under control on Saturday, meaning at least one of the affected tunnels – under the Thames near Ebbsfleet, not under the Channel itself – could be used.
Speed restrictions and uncertainty surrounding the second tunnel meant further disruption was possible, Eurotunnel warned.
The flooding also disrupted Southeastern railway services, and delays and cancellations were expected on some other domestic routes on Sunday due to staff shortages and bad weather.
On Saturday, Eurostar customers were stuck in London and mainland Europe.
A Eurostar statement said: “Flooding in the Thames tunnels has been brought under control by Network Rail High Speed, meaning at least one tunnel can now be used and a full service can operate.
“There will be some speed restrictions in place in the morning which may lead to delays and stations are expected to be very busy.
“Unfortunately, this unprecedented event has caused major disruption to customers today [Saturday]. Customers are encouraged to visit the Eurostar website for more information on their journey and compensation entitlement.”
A spokesperson for HS1, which runs the route between London and the Channel tunnel, said: “Flooding in the Thames Tunnel is being resolved by Network Rail High Speed and the HS1 line will be operational in the morning.
“We understand how frustrating this has been for passengers and apologise for the inconvenience caused at such an important time of the year.”
The problem began on Friday night when water filled tunnels near Ebbsfleet International in Kent, preventing all high-speed services.
The issue was believed to have been caused by a burst pipe feeding the tunnel’s fire safety system, a water company said. Footage shot in the tunnel showed water gushing from a pipe and submerging the tracks.
Thames Water said it believed the flood was caused by a “fire control system and not a Thames Water pipe”.
On Saturday afternoon, engineers working in the tunnel said the volume of water had been “unprecedented”.
A Met Office spokesperson told the PA news agency the problem was unlikely to have been caused by bad weather because there had been no heavy rain overnight or in the area.
Separately, there was major disruption to Thameslink services through London and across the south-east due to a shortage of train crew that would continue into Sunday, the operator said.
The Met Office has warned there could be disruption to domestic journeys throughout the weekend due to windy conditions across the UK. A warning for rain and snow has been issued for much of Scotland.
With PA Media
