TSSA leader Manuel Cortes is calling for “extra vigilance” on Eurostar after a series of rail disruptions caused by protesters.

The union’s leader is seeking a meeting with Eurostar to discuss rail safety measures after a man was arrested for staging a rooftop protest at St Pancras International Station in central London.

The protest caused widespread cancellations of services to mainland Europe.

British Transport Police (BTP) is also investigating how circuit-tripping devices were planted on railway tracks in Cambridgeshire and Nottingham.

The devices would have told signalling workers that a train was on a track when there wasn’t, which would have caused chaos.

Mr Cortes said: “Whether a prank or not, we are very concerned at reports pro-Brexit supporters have accessed our rail infrastructure with the aim of causing delays and chaos.  

“All station staff, especially at Eurostar and British Transport Police need to be extra vigilant and bring to justice those responsible for these acts, which are frankly an act of sabotage that could easily escalate into acts of terrorism should the rail network become damaged or staff or passengers harmed.

“Getting onto our rail tracks is both extremely dangerous and an offence. I appeal to those involved in these acts to desist from doing this before someone suffers a serious injury or a fatality.”

A Eurostar spokesperson said: “The safety of our staff and customers is always our top priority and we will continue to work with the authorities and infrastructure providers to deliver a reliable service for travellers.”