Direct high-speed trains could run between London and Bordeaux within two years, under plans floated by France's state railway company.
The trains would take around five hours, roughly similar to the journey time between London and Scottish cities.
They would run from London St Pancras, down High Speed 1 through Kent, and through the Channel Tunnel, before making their way past Paris to southwestern French city.
The owners of HS1 and the channel tunnel infrastructure are already in favour of the new services, and the companies are searching for an operator to run the trains.
Eurostar, which currently operates all high-speed services through the channel tunnel, recently launched a new direct return route to Amsterdam and has previously said it wants to focus on the Dutch destination before opening new routes.
But the success of the direct service to the Netherlands, which has exceeded ridership expectations, could bode well for Bordeaux. Other operators can in theory run services through the tunnel but none have yet got past the planning stage.
Last year the German state railway DB said it was shelving longstanding plans for direct services between London and Frankfurt via Cologne, citing competition from low-cost airlines and other complications.
The new services to Bordeaux are being eyed by rail planners because a new high-speed line connecting Paris with Bordeaux, LGV Sud Europe Atlantique, opened in 2017.
The journey between Paris and Bordeaux now takes only around two hours, putting it within realistic reach of a direct service to London. Trains on the line have a top speed of 320 km/h.
Speaking at the same event at St Pancras station, rail minister Chris Heaton-Harris said the British government wants to encourage further international rail links and suggested Frankfurt, Düsseldorf and Geneva as other potential destinations.
HS1's owners this month published research suggesting that international rail services with journey times of five hours or fewer can capture around a third of the market share from short-haul flights.
For shorter journeys the market share goes even higher, with Eurostar holding around 80 per cent of the travel market between London and Paris, with a journey time of around two hours and 20 minutes.
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