Eurostar is increasing the frequency of its London to Amsterdam services from Tuesday.
The cross-Channel rail operator is adding a third direct daily train to its timetable.
More than 300,000 passengers have travelled on the new route from London to Rotterdam and the Dutch capital since it was launched in April 2018.
Eurostar marked the expansion of services by commissioning a gown made entirely of sunflowers, in celebration of the Van Gogh And The Sunflowers exhibition which opens later this month at the Van Gogh Museum, Amsterdam.
Mike Cooper, chief executive of Eurostar, said: “With environmentally responsible travel rising up the consumer agenda, we’re boosting capacity and offering more flexibility with a third daily service.”
Although UK passengers are able to travel direct for outbound trips, return journeys involve a change of trains in Brussels for passport checks and security screening.
Eurostar has described this as a “temporary measure” while the UK and Dutch governments complete an agreement to allow border screening on departure, as happens in London, Paris and Brussels.
This is expected to be in place by the end of this year.
Eurostar plans to add a fourth daily service once the agreement is reached, with ambitions for a fifth.
The launch of the Amsterdam service helped the firm record a 7% year-on-year increase in passenger numbers to 11 million in 2018.