The boss of Eurostar, the high-speed rail service linking London with Paris and Brussels, has predicted another record-high year in terms of passenger numbers despite Brexit uncertainty and strikes.

Chief executive Mike Cooper, speaking in London this week to mark Eurostar's 25th anniversary, expressed optimism also over a planned merger with the Thalys rail service that takes passengers from France to Belgium, the Netherlands and Germany.

"We are doing well," Cooper told journalists gathered in the British capital on Thursday, but admitted that Eurostar had faced a tough year owing to Brexit, French strikes at Paris Gare du Nord, and unusually "soft" sales over the summer.

"In terms of passenger numbers, we should be upside on the previous year," he added, after the group had already enjoyed a record-high in 2018.

Turning to Brexit -- which was initially scheduled for March 31 this year but is now due on January 31-- Cooper remained upbeat.

"If I look at the year-on-year growth rate that we are seeing, there has been some softness in the summer months. Is that Brexit, is that wider economic uncertainty? I think it's difficult (to be sure)," Cooper said.

Preparing for Brexit "involved a lot of work, but the work we did was before March 31... We were ready, regardless of whether or not there was a deal or 'no-deal'".

Cooper said Eurostar worked alongside the French, Belgian and UK governments, as well as with the European Commission, to make sure that its operating certificate and safety licences were held in a new French legal entity.

In a knife-edge referendum more than three years ago, Britain voted 52 percent in favour of leaving the European Union.

(COMBO) (FILES) This combination of file pictures created on September 27, 2019 shows a Eurostar (L)  on August 29, 2017 near Lesquin, France, and a Thalys train pictured on March 7, 2012 in Seclin, France; Eurostar forecasts another record year despite B
(COMBO) (FILES) This combination of file pictures created on September 27, 2019 shows a Eurostar (L) on August 29, 2017 near Lesquin, France, and a Thalys train pictured on March 7, 2012 in Seclin, France; Eurostar forecasts another record year despite Brexit uncertainties AFP / PHILIPPE HUGUEN

A total "48 percent of the people in Britain voted to remain, and they are people who want to experience foreign cultures, they are people who know that they need to do business in Paris or Brussels or in Amsterdam", Cooper said.

"Those are major commercial cities. Those markets will continue, and grow. Paris and Brussels are more mature markets, but we still believe there is further room for growth."

Cooper said that within six months he would like to launch a direct route from Amsterdam to London, via Rotterdam. Currently passengers much change at Brussels when returning to Britain from the Netherlands.

Taking into account total train and plane journeys between London and Amsterdam, Cooper hopes to grow Eurostar's market share by between 30 and 40 percent, from "eight or nine" percent currently.

"If I look at the next 12 to 24 months of our growth, the big part of that would come from Amsterdam, Paris will continue to grow as a market we believe, so a combination of existing destinations, high-growth on Amsterdam, will provide the development opportunities."

And as from January, Cooper said that for every Eurostar journey between London and the continent, the group would plant one tree, helping to offset its carbon footprint.

In September, Eurostar's majority shareholder, French rail operator SNCF, outlined plans to merge Eurostar with Thalys.

A tie-up would "immediatly... bring growth opportunities in Germany for Eurostar and the reverse is that it would offer potential growth opportunities for Thalys in the UK", Cooper added.

It is hoped that a combined group would transport 30 million passengers a year, compared with 18.5 million in 2018.