In 1941, Britain's fight with Nazi Germany lay in the balance. But no effort was spared to improve the war effort. In November of that year, researchers from the Board of Trade interviewed 5,000 women about their lingerie collections.
The survey was well intentioned - to work out the amount of steel that was being diverted from the war effort to prop up women's corsets and other garments. But it led to unintended humour and, for a modern readership, some surprising answers.
...
Areas of interest ranged from whether moustaches made men more attractive, the speed with which people could drink a half-pint, and how much alfresco sex was taking place in Blackpool during August.
"Blackpool had a reputation for bonking on the beach," says Walton.
"So Mass Observation decided to visit and test the legend out. They went out at night and fell over couples on the beach and noted down how many were having sexual intercourse."
http://www.bbc.co.uk/news/magazine-14746750