Eurostar passengers spent several hours waiting in darkness after two trains were left stranded by a power cut to overhead lines.
Last night's 7.32pm Paris service and 7.34pm Brussels service from London St Pancras were brought to a halt outside Lille, northern France, at around 9pm BST.
Sara Forgione, 27, from Archway, north London, told the BBC: "We had to wait in complete darkness for about two hours and then we had to walk the full length of the train in complete darkness to eventually get off and make our way to the buses."
Around 460 passengers were taken to Brussels, Belgium, on a replacement bus service, arriving several hours later than planned.
The Paris-bound train was towed into Lille station where some 500 passengers were able to transfer to a replacement train.
Around 1,000 passengers have been offered refunds and will be given their return trip for free.
A Eurostar spokesman said today: "Following a power supply problem near Lille, northern France yesterday September 25, all Eurostar services are expected to run.
"However, trains will be subject to delays of up to 30 minutes. Customers are asked to check in as normal."
It is the second power problem this week to affect Eurostar services.
Passengers fled when an overhead power line collapsed on Wednesday as a train pulled into St Pancras.
Nobody was hurt but 11 Eurostar trains in and out of St Pancras were delayed for between an hour and two hours.