Eurostar has seen ticket sales rise 25% in the first six months of 2008.
Tickets sales totalled £368.8m between January and June 2009 – an increase of 24.7% on the same period last year.
Traveller numbers reached 4.63m, an increase of 18.3% on 2007.
Cities seeing the strongest growth include Derby, Nottingham, Sheffield and York.
From September 8, Eurostar is adding an eighteenth daily service each way on the London to Paris route. This will provide a half hourly service in the morning and evening peak times.
Eurostar chief executive Richard Brown said: “This impressive growth in passenger numbers clearly demonstrates that Eurostar’s move to St Pancras International has opened up high speed rail to millions more people across the UK.
“The impact of rising oil prices, combined with growing awareness of the much greater environmental impact of flying, are causing more and more travellers to switch from plane to train.”
The rate of growth is likely to slow in the second half of the year because of the economic downturn, he added.