Thousands of passengers have had their travel plans thrown into chaos after Eurostar cancelled all services to and from St Pancras when a trespasser was caught brandishing a St George’s flag.

The 44-year-old spent the night on the roof of a tunnel leading away from the central London station, bringing Eurostar services to a halt before he was arrested by police on Saturday morning.

Eurostar was forced to cancel at least eight trains, sparking disruption for the weekend getaway, due to the man being in “a precarious position”.

An image showed the man standing in the middle of a tunnel entrance roof several hundred yards away from the station clutching the flag as police looked on.

Wanna know why St Pancras and all the trains are messed up? The flag waving bell-end is on top of high speed tracks. pic.twitter.com/2U2g5TAR3I — Tasha S (@tic_tash_toe) March 30, 2019

Passengers vented their frustration on Twitter. One tweeted: “I am not able to check in this morning at St Pancras because of a ‘trespasser’ and I have hotels booked in Brussels that I cannot now cancel and receive a refund.”

One woman described how she was left hundreds of pounds out of pocket and “fed up” after her Mother’s Day treat had been scuppered by the cancellations.

Catherine Inkster organised a weekend break for her mother in Lille, France, but the pair were eventually forced to scrap their plans. They spent four hours waiting in a lounge at St Pancras on Friday evening before finding out their train had been cancelled.

“There was this huge line, hundreds of people, and obviously there were no Eurostar staff, at least not visible to me,” she said.

Inkster and her mother had to shell out £125 for a hotel in the capital before rising with just three hours’ sleep for a rebooked train, only to find out they could not travel on Saturday morning either because of further cancellations. “Initially we had been advised it was likely to run. We arrived at 6.15am to find the same situation. No one going through the gate. The Eurostar staff just didn’t know what was going on.”

“I’m very frustrated, fed up and out of pocket,” Inkster, who is from south London and works in sports PR, said. “More than anything, I was surprised at how long it took for the police to resolve the situation, given it was a lone protester from what it seems.”

Inkster had already spent £450 for accommodation in Lille. She and her mother have scrapped their plans to go to the continent and are going to spend the weekend in Brighton instead.

Police were called to investigate at 7pm on Friday after the man was spotted on the roof. It quickly led to disruption, with Eurostar cancelling the 7.34pm service from St Pancras to Brussels. Further services were cancelled to and from the station until 9.45am on Saturday morning.

The man’s presence meant that overhead lines had to be switched off, leading to further disruption on Southeastern services heading towards the station from Kent.

British Transport Police said: “A 44-year-old man has this morning been arrested for trespass and obstruction of the railway, having spent the night on the roof of St Pancras railway station.”

A Eurostar spokesman said: “We have suspended all services to and from London St Pancras until 9.45am, due to a trespasser on the tracks.

“We strongly recommend you not travel this morning and please cancel your journey or exchange ticket free of charge.”

Southeastern tweeted earlier on Saturday morning: “SERVICE UPDATE: High Speed trains will not run to and from #StPancras due to the ongoing trespass incident just outside the station. The person is above the High Speed lines and as such the overhead wires can not be recharged. Please use mainline trains to Victoria or Charing X.”

Eurostar announced shortly before 9am that services would resume soon.

A Eurostar spokeswoman added: “Because of a trespasser near the tracks, we were not allowed to run any services in or out of St Pancras. Therefore we had to temporarily suspend services. The trespasser has now been apprehended and our services will be able to start to run in the area again soon.”

Eurostar trains eventually re-started at around 11am.