Passenger numbers on Eurostar rose to record levels during this summer's security chaos at UK airports, it was announced today.

Eurostar, which runs services out of London Waterloo to Paris and Brussels, said thousands of passengers had switched from plane to train after the extra security measures at airports had led to flight delays and cancellations.

The company carried 2.15m passengers between July and September this year - up 9.9% on the same period last year and the company's highest-ever figure for the summer period. Eurostar's profits for the same period were up 21% to £130.4 million, with 91.4% of its trains running on time.

The company's communications director, Simon Montague, said today: "It has been an outstanding third quarter for Eurostar. The surge in traveller numbers has been driven by the delays at UK airports. Business travellers in particular are continuing to switch to Eurostar from the airlines. "We have been surprised and pleased at the increasing number of passengers who say that the environment is a growing reason for switching to Eurostar, and who are prepared to make Eurostar part of longer, connecting rail journeys than in the past."

Independent research published last month showed that a passenger who flies between London and Paris or Brussels generates 10 times more emissions of carbon dioxide than one who goes by Eurostar. A return flight emits enough CO2 to fill a double-decker bus, while a train journey only generates enough to fill a Mini.

Mr Montague said: "We expect concern about transport emissions to become an increasingly important factor in passengers' travel decisions in future. The latest figures also show clearly that the inbound tourism market to the UK has fully recovered from the effects of the terrorist attacks in London in July 2005."

Railway holiday company Great Rail Journeys, which also operates out of Waterloo, said that it too had enjoyed a huge increase in demand since the terror alerts. The company reported a growth in sales of more than 85% between August and October this year compared with the same period last year.

Managing Director Steve Kimber said: "Demand has been exceedingly strong, with sales in many weeks more than doubled since August. As well as being a more relaxing holiday, customers appreciate the fact that trains offer a credible green alternative to travelling by air, generating substantially less CO2. We expect 2007 to be another bumper year for the company."

Meanwhile, Virgin Railways said it had carried more passengers during the period of airport delays, especially on its London-Glasgow service. However, a spokesman said that the company's passenger numbers had been rising anyway (10% year-on-year on the London-Glasgow line), so it was difficult to say how much of the extra business had been due to the airport chaos.