From bra ownership to television interference, the government has wanted to know some strange stuff about people in the UK. Now a history of social surveys reveals why.

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.

It showed that on average women in 1941 owned 1.2 such items of underwear each. There were some strange variations, with housewives owning 0.8 brassieres but agricultural workers 1.9.

The report explained its purpose with a lofty air: "Only with this information can the greatest efficiency in planning be secured. It was therefore felt that detailed information should be secured on a subject which is of interest to most women - foundation garments."

The underwear survey is just one of a number of studies being highlighted by the Office for National Statistics (ONS) to mark the 70th anniversary of its social surveys. Others are shocking rather than amusing, such as the 1951 survey looking at "public attitudes towards coloured people".

Image caption Planes and televisions did not mix well in 1961

Another brings up period detail. In a 1961 survey on attitudes to aircraft noise, 78% of people complained that planes at Heathrow made their television flicker.

In 1981, alarm over the amount women were drinking caused a survey to be undertaken by ONS. Yet the investigation found more than 70% of women drank fewer than five units a week. These days the average figure is eight units a week, with a unit equalling a small glass of wine.

In the 1990s the ONS looked at smoking in secondary schools and in 2001 turned its attention to sex and contraception - not an area where a 1950s government statistician would have ventured.

Bananas diverted

Pollster Peter Kellner's mother worked as a social survey fieldworker for the state during World War II. Her inquiries addressed life on the home front and occasionally yielded strange results.

Blackpool had a reputation for bonking on the beach Dr John Walton

"In Middlesbrough she came across a child who needed bananas in her diet to survive," he recalls. "In those days bananas were almost impossible to get. But as a result of her discovery, the tiny supply Britain had was diverted to Middlesbrough to keep the girl alive."

Kellner, president of YouGov, is not surprised that 1941 researchers were interested in the availability of women's underwear. "At a time of war it was incredibly important to know what the population was up to and how rationing was affecting them."

The survey is a rich source for future generations, says social historian Juliet Gardiner. "The questions are interesting because they reflect the preoccupations of the society. These worries can be quite hard for the historian to uncover."

There have always been attempts by rulers to measure social change, from the Domesday Book of William the Conqueror to the census, which began in Britain in 1801. But in recent years, the boundaries have been pushed by independent organisations rather than government.

And such surveys can sometimes outrage the authorities, says Andrew Phelps, who managed the National Centre for Social Research's latest sex survey. The first of these sex surveys in 1990 had to find new backers after the Thatcher government pulled the plug.

"It almost got handbagged by Maggie. It was seen as too intrusive - they said people wouldn't tell the truth. And they were perhaps worried that it would show the British in too subversive a light."

The survey, now in its third decade, is today supported by research foundations and provides information on sexual behaviour that informs government policy.

It asks interviewees about the number of recent sexual partners, erectile dysfunction and sexuality. And at the end the respondent is asked to provide a urine sample to measure sexually transmitted diseases.

"Believe it or not about two-thirds of people are fine with that," Phelps says.

Alfresco sex

Dr John Walton, author of Fish and Chips and the British Working Class, says Britain has a long tradition of asking the population apparently absurd questions.

In the 1930s civil servants from the fisheries ministry toured the country asking people about fish and chip consumption. As well as the ubiquitous cod and haddock, they found Geordies ate coalfish, while Londoners opted for hake.

Then there was Mass Observation, an ambitious project launched in the 1930s by the polymath Tom Harrisson. The aim was to record the way ordinary Britons lived, using diaries, questionnaires and by following people around and noting down their habits.

Image caption More or less attractive? The Mass Observation project was interested in moustaches

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."

They recorded four such cases, only to have the study reliability jeopardised when it emerged that one of the participants was a Mass Observation researcher.

"I like Mass Observation because a lot of their questions are asked with blue skies curiosity," he says, whereas many social surveys today are policy-driven by government and so can fall prey to a particular agenda or ideological fashion.

A lot has changed since the ONS began its social surveys. Today the organisation can call upon an army of 1,000 interviewers, far more than the number doing the job in 1941.

And now the social survey is heading into new, and some might argue unmeasurable, territory - personal well-being.

"Overall, how happy did you feel yesterday?" and "Overall, to what extent do you feel the things you do in your life are worthwhile?" are two questions that may surprise ONS statisticians from earlier eras.

So will future generations be poring over the answers in a similar way to our fascination with the 20th Century social surveys? Undoubtedly, says Gardiner.

"The well-being survey will be hugely interesting to future historians. They'll be fascinated by the idea that you can quantify happiness and be intrigued by what indices you use to do that."