The trouble being faced by some airlines will mean there will be interest when Eurostar's monopoly on the Eurotunnel ends in two years' time, according to an expert.
Sharron Livingston, editor of www.thetravelmagazine.net, said that customers could expect better services and reduced fares on the trains, which airlines will have to compete with.
After Air France-KLM announced they plan to launch a train service, Ms Livingston said it was "impossible to predict" which firms might next turn to rail travel as "another string to their bow".
The Channel Tunnel opened in May 1994 and says it has been used by more than 212 million people in the last 14 years. Eurotunnel shuttles have carried the bulk of people, at almost 128 million and Eurostar has carried nearly 85 million passengers.
It is claimed that the average time it takes to travel between London and Paris on the Eurostar is two and a quarter hours.
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