The tourist boom enjoyed by London in the wake of the Olympics could be wiped out by next year's increase in airport departure tax, tourism officials have warned.
Around 84% of those questioned in a survey said tourism to the capital would be damaged if the planned rise in Air Passenger Duty (APD) goes ahead next April.
And the majority of holidaymakers questioned by the World Travel Market (WTM) also said their travel plans could be affected by an increase in APD.
APD is charged on the carriage of passengers flying from a UK airport on an aircraft that has an authorised take-off weight of more than 10 tonnes or more than 20 seats for passengers.
It varies between £13 and £184 per passenger, depending on the type of seating they use and the distance they are travelling.
The increase that is expected to take effect next year is thought to be in line with inflation.
Around half of the 1,300 tourism officials questioned for the WTM survey thought the higher resulting air fares from an APD increase would particularly affect people visiting from the growing Bric (Chicago Options: ^RBRCTRUSD - news) zone of countries.
This refers to the Brazilian, Russian, Indian, Chinese and South African markets, with Brazilians supposedly the most likely to be put off coming to London.
Of the 1,001 holidaymakers who were surveyed by WTM, more than half said a rise in APD would lead to them altering their holiday plans.
Some said they were likely to swap long-haul trips for short-haul ones. Other respondents said they might book fewer holidays, while around 18% were unsure what they would do.
WTM director Simon Press said: "It's heartbreaking to think the good work of an entire nation (from the Olympics) can be wiped out in an instant by the greed of the Government.
"APD has long been a punitive tax on tourism and its increase will make it even more so and ironically will most likely drive down revenues as fewer tourists come to the UK as a result."