Night has now fallen on the train, which is stranded on a track in east Kent.
The Independent spoke to one of the passengers, Ben Williams, seven hours after the train ground to a halt.
He said: “We got as far as just before the Eurotunnel and then we were told that we would have to wait before going into the tunnel. Slowly over a period of a couple of hours, we found out it was a bit more serious than that. Some sort of issue with the cables – electric cables – and the train just lost all power, basically.
“The train has not had any power now for at least five hours. The toilets haven’t been functioning properly.
“They can’t do the announcements.”
After several hours the train was “dragged for about 10 or 15 minutes” but then stopped again.
“I think the staff are all very stressed themselves, and I don’t think they’re being kept very well up to date,” Mr Williams said.
“We were offered one free food item that was after we’d been stationary for about four or five hours. By that point, I’d already bought myself a sandwich, having been stationary for a couple of hours.
“To be honest, I’ve been pacing myself just because obviously the toilets aren’t functioning.”
Mr Williams was on his way to visit a friend in Amsterdam for the weekend. Eurostar has not said what the exact nature of the problem is, nor what arrangements will be made to get passengers to their destinations.
Eurostar wrote on Twitter/X: “We’re sorry for the delay to the #ES9114 today. The train is being detached from the overhead power lines but this is taking longer than expected. Due to a lack of power on board, it’s not possible for announcements to be made. We apologise for the inconvenience.”
This was updated an hour later: “We’re awaiting authorisation from the infrastructure managers to proceed and hope to get you back to London as soon as possible. Thanks for your patience.”
At 4.10pm, Eurostar announced: “The train is now on the move and arrangements are being made to bring passengers back to London.”
Mr Williams confirmed that the train moved briefly but then stopped.
He said he was alarmed at the apparent lack of preparation: “Surely this sort of thing has happened before. They must have some kind of contingency plan in place so that people can use toilets properly and maybe get given some bottles of water and food after three or four hours?
“Unfortunately for the staff on the train, no one’s given them logistical support from head office. So they’re just having to deal with p***ed off customers, basically.”
The train eventually started moving back to London, arriving at 5.15 – nine hours after departure.
On Friday morning a spokesperson for Eurostar said: “Yesterday, an overhead cable had fallen on the 8.16am Eurostar train, between London and Amsterdam, at the entrance of the Channel Tunnel. There were around 700 passengers and crew on board who were confirmed safe.
“Following a complicated situation due to the position of the train and the track infrastructure, certain safety procedures had to be adhered to before the train could move. Further to this, the collapse of the overhead line meant that power was out on the train.
“The backup battery power on board expired after a few hours, putting the lighting, heat toilets and public address systems out of service. During the disruption, food and beverages were provided with emergency provision available.
“Eurostar is very sorry for what our customers had to experience. Eurostar and its staff prides itself on running a reliable service. We are taking immediate action into reviewing how the disruption was handled especially the processes and communication with infrastructure partners.”
Passengers are being offered a full refund, and a voucher worth twice the value of the original ticket.
Hotels, taxi and subsistence costs will also be refunded to passengers who stayed overnight in London.