The extraordinary drama saw the unidentified man – who is in his 40s and believed to be from Liverpool – being hauled off the train after it made an emergency stop in Lille, northern France.
He was then surrounded by at least eight uniformed officers, and then left stranded when the train resumed its journey to England.
“I’ve done nothing wrong and respect all coronavirus rules – this is absolutely outrageous,” he said, as he was led away in front of other stunned passengers on Thursday afternoon.
He added: “I have absolutely no idea what this is all about, except that a Eurostar staff member has taken a very strong dislike to me, and accused me of not wearing the right type of mask.
“Now I’m going to be left alone in France, when all I wanted to do is get home from a work trip. This is very cruel treatment. We should all be getting on, not treating each other like this.”
Other passengers then complained about the unscheduled, unannounced stop in Lille that caused a delay of some 15 minutes.
“Why is Eurostar stopping its trains, and delaying hundreds of passengers, because of a petty dispute over one man’s mask?” said one.
The female Eurostar manager – who remained on the train after the man was taken into custody – confirmed she had reported him for wearing the “wrong type of mask” for preventing the spread of coronavirus.
Asked why the man had been forced off the train, one of the Lille police officers confirmed he had been arrested, and said: “We don’t know why, we’ll have to find out.”
The drama unfolded soon after Eurostar 9031 left Paris Gare du Nord on time at 1.13pm French time on Thursday.
It was due to travel direct to London, so as to arrive at St Pancras at 2.39pm UK time – just under two-and-a-half hours later.
Within minutes of departure, the Eurostar manager was involved in a heated argument with the man, however.
She accused him of not complying with health and safety regulations, and said the black mask he was wearing was not appropriate.
All Eurostar passengers are expected to wear masks at all times, except for when they are eating or drinking.
There was a buffet on the train, and many of the passengers in Coach 13 – where the man was sitting alone by a window in a two-seat row – had removed their masks completely, as they had sandwiches and drinks with them.
Despite this, the manager berated the man, and then used a radio to summon another member of staff.
She then said she would be alerting police at Lille, to make sure that the man was removed “as quickly as possible”.
The businessman then replaced his black mask with a standard blue one provided by another passenger. He apologised, and appeared to have escaped any further action.
But when the train got to Lille it made an unscheduled stop, and three armed officers boarded, while the others waiting on the platform.
“It was ridiculous,” said another passenger, a 32-year-old London woman who asked to be referred to by her first name, Li.
“The Eurostar woman was telling the police what to do, and insisting that the poor guy should be removed, like he was some kind of criminal.
“He was actually being very reasonable, and not swearing or acting in any kind of disruptive way at all – everybody else was on his side, but he was marched off and we didn’t see him again.”
The Eurostar manager remained on the train until St-Pancras, and was seen leaving the train with a rucksack.
Eurostar later issued a statement about the man’s arrest by police.
It read: “Eurostar’s conditions of carriage clearly state that face masks must be worn for the entire journey within the stations and on board, and that failure to comply may result in refusal to travel.
“Unfortunately, a passenger on board a service from Paris to the UK on Thursday repeatedly removed his mask both in the station and on board, despite gentle reminders from staff.
“During the journey, the passenger became aggressive and intimidating towards the on-board team, when they politely reminded him to wear a mask as is required under our conditions of carriage.
“Eurostar teams have a responsibility to ensure the safety of all of those on board, and this kind of behaviour towards our staff cannot be tolerated. As a result, the passenger was asked to leave the train at Lille station and in this situation it is normal procedure for the police to attend and assist.”