A full investigation should be carried out after thousands of passengers were stranded on trains for several hours, according to a public transport watchdog.

London TravelWatch issued the demand as it expressed concern over the “lack of communication and slow response time” following damage to overhead electric cables in west London on Thursday night.

Passengers reported being stuck for more than three hours on dark, cold trains while receiving no information.

Around seven trains were stranded, operated by the Elizabeth line, Heathrow Express and Great Western Railway (GWR).

Elizabeth line trains have no toilets, adding to the discomfort for those on board.

GWR told passengers that one of its trains “struck an obstruction on the line causing damage to the overhead electric wires”.

The Great Western main line was already being investigated by the Office of Rail and Road over poor reliability.

Four damaged rails were discovered within eight days last month.

London TravelWatch said in a statement: “Passengers stranded on trains endured nightmare journeys on Thursday evening.

“You can imagine how unpleasant it must have been for people stuck for more than three hours. As power was cut, the trains became cold and dark.

“The apparent lack of communication and slow response time to get passengers off to a place of safety is just as concerning.

“We have heard reports that some passengers even tried to open the doors themselves to self-evacuate.

“This is extremely dangerous which is why clear information and a swift co-ordinated response is a must in emergency situations like this.

“We expect TfL, Elizabeth line, Network Rail and other authorities involved to investigate this incident thoroughly.

“Lessons need to be learned so if this sort of thing does ever happen again, both the communication and response is vastly improved.”

In March 2018, dozens of passengers evacuated themselves when several trains were stranded in severe weather in Lewisham, south-east London.

Singer James Blunt and TV presenter Rachel Riley were among those affected by the disruption on Thursday.

Blunt posted on X: “Been stuck somewhere outside Paddington for close to 4 hours now. Out of peanuts and wine”, while Riley wrote: “Nearly 4 hours after we got on, we’re getting off the Elizabeth line, woohoo!”

Mikey Worrall, who was stranded on an Elizabeth line service, said the train lurched to a stop and then there was a multiple-hour wait in semi-darkness as the driver drip-fed what little information they had to passengers.

Eventually, the battery backup running the train’s heating and light services ran out, and passengers were left in darkness for another hour and a half until they were evacuated.

Mr Worrall told the PA news agency: “We saw a couple of workers come past and they were trying to keep everyone calm. Suddenly, we saw a stream of people coming down the track and at that point it was clear that we would be getting off.

“It was really eerie walking down the railway line in amongst this big crowd of people. It felt like a wartime thing.”

Engineers worked through the night to get two of the four lines serving Paddington open for electric trains, but disruption continued on Friday.

A Network Rail spokesman said: “We are so sorry for the difficult journeys passengers endured on our railway last night and we will be investigating how and why it happened.

“The knock-on effects from last night mean operators will not be able to run a full service from Paddington today and passengers should check before they travel.

“Repairs are ongoing and we hope to have the railway fully open by the weekend.”

Transport for London (TfL) said in a statement: “We’re sorry that the damage caused to Network Rail’s overhead power lines by another rail operator’s train has caused significant disruption to our Elizabeth line customers as well as all train operators out of London Paddington.

“We worked to get customers off stranded trains as quickly as possible and to provide any support needed.”

Aslef said a manager was driving the train involved in the incident after being drafted in to cover for a strike.

Members of the union at GWR walked out on Thursday as part of a long-running dispute over pay.

The union said other train operators had chosen “quite sensibly” not to run any services during strikes.

A GWR spokesperson said: “The only people who can drive our trains are competent train drivers with route knowledge.

“That would include train driving instructors.”