Air France was last week mistakenly accused of launching a new fee for obese fliers which has re-ignited the debate over whether airlines should charge more when an extra seat is needed.

The airline maintains that although it does currently have a system whereby obese passengers are given a 25 per cent discount off their second seat, new legislation next month will entitle obese customers to a full refund, provided their flight is not fully booked.

Less than a quarter of the 550 people surveyed disapproved of forcing those who can not fit into a standard airline seat to purchase a second seat, normally at a discounted rate. Others suggested that charges should be calculated on the weight of the person and baggage combined.

In April last year Ryanair said that it was considering whether to charge excess weight fees for obese fliers after more than 30,000 passengers voted in online poll in favour of such charges.

In 2008, Air France was ordered to pay £5,000 in damages to a 27-stone passenger who had his waist measured at an airport check-in desk before being told he would have to purchase two seats.

“The so called ‘Fat Tax’ is a very sensitive issue for airlines - they will have to tread carefully so as not to alienate heavier passengers,” said Barry Smith, Skyscanner co-founder and director. “On one hand, it’s not unreasonable for airlines to charge passengers extra if they occupy more than one seat. On the other, many would argue that it should be the responsibility of airlines to adjust their standard seat size, enabling them to comfortably accommodate all passengers.”

According to the World Health Organisation the Pacific island of Nauru is currently classified as the world’s fattest country with 94.5 per cent of the population overweight. Britain is in 28th position, with nearly 64 per cent of the population considered to be overweight.