The heatwave has hit profits at Thomas Cook. In its third-quarter trading statement, the giant tour operator said that gross profits had slipped by 3 per cent for the three months from April to June.

“We expect full-year profits to be at the lower end of market expectations, said the chief executive, Peter Fankhauser.

Warm weather has delayed decisions to book. he said. “The heatwave has meant there are more holidays for tour operators to sell in the lates market.

“We still have about 20 per cent [of summer package holidays] left to sell.

“The weather is something we can’t control.”

Thomas Cook’s underlying performance, though, was solid. Group revenue for the quarter increased by 10 per cent to almost £2.5 billion, which the company said was driven by strong demand for Turkey and North Africa.

“Turkey is the stand-out destination,” said the chief executive. “In the UK, we have seen 63 per cent growth.”

Antalya has taken over from Palma de Mallorca as the leading overseas airport served by Thomas Cook.

Thomas Cook was also the first major tour operator to return to Tunisia, three years after two terrorist atrocities against tourists.

Mr Fankhauser criticised staff shortages at air-traffic control centres in Europe, particularly at Mannheim in Germany. “We had a really, really tough start to the season,” he told The Independent.

Other airlines, notably Ryanair, have also blamed air-traffic shortcomings for delays and cancellations this summer.

Holidaymakers are paying higher average prices compared with last summer, largely due to accommodation prices in Spain, but the company said: “Average selling prices are 3 per cent lower overall, reflecting a higher mix of short/medium-haul destinations.”