As thousands of holidaymakers head for the sun on the busiest weekend of the year for airports, David Chidgey, the Liberal Democrats' trade and industry spokesman, has revealed that the average male has grown by three quarters of an inch since the rules were drawn up. People travelling on charter flights are squeezed hardest by the change; many larger airlines leave more than the minimum space.
While the national average height used to be five feet eight and a half inches, it is now more than five feet nine inches. This has meant increasing discomfort and even a safety risk for anyone over six feet tall.
The regulations governing the amount of space per passenger were drawn up in 1989 by the Civil Aviation Authority but are believed to have been based on a height survey carried out in 1980.
They were designed to ensure that all but the tallest five per cent of men could sit on planes without having their knees rammed into the back of the person in front. But young men are growing ever taller, and twice as many under-35s are now too big for their seats.
Mr Chidgey, who has received representations from some of his taller constituents on the subject, has launched what he describes as "a crusade on behalf of the squeezed and squashed air passengers of Britain".
He says that passengers who are of more than the regulation height could be at greater risk than their neighbours in an accident because they might find it difficult to get out of the plane in an evacuation.
"The Government must respond to these shocking revelations with an urgent review of the seat size regulations. Until they do Britain's taller jet setters will not be able to rest easily in their airline seats," he said.
Mr Chidgey, the member for Eastleigh, has written to the transport minister Glenda Jackson to ask her to review the basis of the regulations. However, she has already indicated in a parliamentary answer that she is unlikely to do so.
"There is no reason why an individual who falls outside the range used by the Civil Aviation Authority should be at greater risk during an emergency evacuation. There has been no significant change in the data since 1989 and the CAA have no proposals to review this standard," she said.