By Mark Easton
BBC News Home Editor
Britain is less happy than in the 1950s - despite the fact that we are three times richer.
The proportion of people saying they are "very happy" has fallen from 52% in 1957 to just 36% today.
The opinion poll by GfK NOP for The Happiness Formula series on BBC Two provides the first evidence that Britain's happiness levels are declining - a trend already well documented in the United States.
Polling data from Gallup throughout the 1950s shows happiness levels above what they are today, suggesting that our extra wealth has not brought extra well-being.
It could even be making matters worse.
The British experience mirrors data from America, where social scientists have seen levels of life satisfaction gradually decline over the last quarter of a century.
Happiness levels were higher in post-war Britain
In the early 1970s, 34% of those interviewed in the General Social Survey described themselves as "very happy".
By the late 1990s, the figure was 30% - a small but statistically significant drop.
The story of wealth failing to translate into extra happiness is the story of the Western world.
In almost every developed country, happiness levels have remained largely static over the past 50 years - despite huge increases in income.
What the happiness research suggests is that once average incomes reach about £10,000 a year, extra money does not make a country any happier.
How does Britain compare?
Our poll asked people how satisfied they were with their lives as a whole using a one to 10 scale.
The mean score was 7.3 which puts the UK some way down the world rankings.
One recent table has Switzerland as the happiest country, followed by Denmark, Sweden, Ireland and the USA. Britain comes eighth.
The Happiness Formula
Wednesday, 3 March
1900 BST on BBC Two
Many different organisations, including the United Nations, have attempted to compare the happiness rates of different countries.
Should politicians try to make us happier?
In our opinion poll we asked whether the government's prime objective should be the "greatest happiness" or the "greatest wealth".
A remarkable 81% wanted happiness as the goal. Only 13% wanted greatest wealth.
Should schoolchildren be taught how to be happy?
GfK NOP asked people whether they thought schools should put more emphasis on teaching students how to achieve a happy personal life and less on educating them for the world of work.
A majority - 52% agreed that more emphasis should be placed on happiness - 43% disagreed.
Our poll asked whether people felt their neighbourhood was more or less friendly now than it was 10 years ago.
43% said less friendly, compared to 22% of people who said it was friendlier.
So what makes us happy? Almost half of people - 48% - say that relationships are the biggest factor in making them happy. Second is health on 24%.
When we asked people to choose the two most important sources of happiness in their lives, out of 1001 people only 77 people said work fulfilment.
According to the science of happiness, friends are crucial to our well-being.
Yet according to our opinion poll, most of us speak to only a small number of close friends every week.
Six out of 10 people spoke to five friends or fewer each week.
Two out of 10 spoke to only one or two friends. And one person in 25 talked to no friends at all.
We also asked people to say, in their own words, what happiness meant to them.
According to analysis by Ilona Boniwell, a psychologist at Oxford Brookes University, most people's definition involved family and friends.
But the results threw up a surprise. The second largest group of responses centred around contentment and inner peace.
It does appear that many people's happiness is about escaping the stress and pace of modern life.
It has been suggested that rising levels of stress and depression may indicate that Britain is becoming more unhappy.
However, it is not clear whether clinical diagnoses reflect a real fall in happiness or a greater willingness to seek help for psychological problems.
Research throughout the world suggests that most people are slightly to moderately happy, and only a few people say they are unhappy.
The Happiness Formula poll found that 92% of people described themselves as either fairly happy or very happy. Only 8% said they were fairly unhappy or very unhappy.
Professor Ed Diener, a leading psychologist based at the University of Illinois, said: "The idea that modern society is a sink of unhappiness seems wrong".
However, average happiness scores do appear to be static or falling.
Nearly half of married people told us they are "very happy". Only a quarter of singles said the same.
Researchers believe the key factor is the promise to stay together.
Is happiness linked to health?
GfK NOP asked people how they would describe their state of health.
Among those who described themselves as "very happy", 45% said they had "very good" health.
Among those only "fairly happy" 23% said they had "very good" health.
Our opinion poll asked whether people would take a legally available drug that made them happy if there were no side-effects.
Nearly three out of four, 72%, of people said no and 26% said yes.
The GfK NOP opinion poll for The Happiness Formula series was conducted by telephone. The fieldwork was carried out between 28-30 October 2005. The sample size was 1001 adults aged 15 or over, and the margin of error is +/- 3%.
Mark Easton presents The Happiness Formula series. The first programme was broadcast on BBC Two on Wednesday 3 May at 1900 BST and will be broadcast at the same time for the following five weeks.