Hundreds of passengers have been stuck on board a Eurostar train amid cancellations on its network due to power issues.
Travellers said on social media that they had been “trapped” inside carriages on a train in Belgium in scorching temperatures.
Pictures showed people being helped off a stationary Eurostar train by workers and videos showed passengers sheltering from the heat in a tunnel.
Eurostar said that it was working to resolve power issues which had caused one train to be held on tracks, and that doors were opened to provide ventilation.
Other travellers said they had been offloaded from Eurostar services before they reached their destination.
At least two services between London and Brussels had been cancelled at 13:00 BST with passengers offered refunds or free transfers.
Temperatures in Brussels reached 36C on Wednesday afternoon.
A replacement service has been sent from the city to collect affected travellers, Eurostar said.
“Customers with bookings this afternoon should check our website for any cancellations caused as a knock-on effect and we apologies for any inconvenience caused,” the company said in a statement.
It added: “Due to the high temperatures today doors were opened to provide ventilation, and steps are in place so that those that would prefer to wait in fresh air are able to do so.”
The company advised those expecting to travel on its services later on Wednesday to check its website for updates.
In Britain, Network Rail said it had activated an “extreme weather action team” to cope with the country’s 38C heatwave.