I see this has been answered in the past but I want to check if it is the same nowadays. I have a UK visa and a Schengen visa issued by the Swiss embassy.
We're traveling to London and then taking the Eurostar to Paris. We have confirmed bookings of hotels and flights. Paris to Nice, and then Nice to Geneva.
Would it be a problem in London to board the Eurostar?
A relative of mine was refused a connecting flight on Turkish Airlines from Turkey to an EU country that did not issue the Schengen visa, hence asking.