LONDON BRIEFING:ECONOMIC GROWTH is not the only way to measure a nation's prosperity.

From next month, Britain’s statisticians begin the task of assessing how happy we all are, responding to David Cameron’s oft-repeated view that there’s more to life than money.

The prime minister wants economists and policy-makers to focus not just on GDP, which since 1948 has been viewed as the critical measure of the nation’s prosperity, but on “GWB – general well-being”.

Statisticians at the Office for National Statistics will poll 200,000 people, asking them a series of four questions:

How happy did you feel yesterday?

How anxious did you feel yesterday?

How satisfied are you with your life nowadays?

To what extent do you feel the things you do in your life are worthwhile?

Those interviewed will score their levels of contentment on a scale of one to 10.

The statisticians aim to produce a national happiness index that will be released each quarter, in much the same way that data on gross domestic product is currently published.

The first findings are due in mid-2012.

The government has given the statistics office an annual budget of £2 million to get the happiness index up and running and it will ultimately extend its range of questions to include numerous other aspects of people’s lives.

All of which raises the question of what a government’s objective should be – the greatest wealth of the population or its greatest happiness?

While research shows that the richer you are, the happier you tend to be – little surprise there – there comes a point in developed countries where increased economic wealth no longer feeds through to greater well-being.

In Britain for example, economic output has almost doubled since 1973, while happiness levels have remained flat.

The prime minister is keen to utilise the findings in shaping economic and social policies and to compare Britain’s progress in the years ahead against other nations.

Among politicians, France’s Nicolas Sarkozy has led the way. In 2008, before the global financial crisis struck, he set up a commission of 20 economists, headed by Nobel laureate Joseph Stiglitz, to report on how happiness could be incorporated into the national statistics.

They looked at a broad range of measures, from the time spent sitting in traffic jams to equality between men and women in the workplace.

While Sarkozy’s initiative was dismissed as “tree-hugging nonsense”, particularly in the United States, politicians are increasingly acknowledging the limitations of measuring a country’s prosperity in narrow output terms.

A number of other economists have studied “happinomics”, notably David Blanchflower, the former Bank of England monetary policy committee member who is often referred to as a “happiness guru” because of his work in this area.

Blanchflower’s research has highlighted a number of factors affecting happiness, from age to marital status and frequency of sexual intercourse.

In a 2007 paper, Hypertension and Happiness Across Nations, he and fellow economist Andrew Oswald found that “happier” countries reported less hypertension (implications here for life expectancy and healthcare spending) and suggested that blood pressure readings would one day make up part of a new well-being index.

It will be years, perhaps even decades, before “GWB” data will be sophisticated enough to be of any real use, but its development certainly presents a challenge to practitioners of the so-called miserable science – and might even win them a more cheerful new name.

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Mervyn King celebrated the 20th anniversary of his arrival at Britain’s central bank yesterday at Westminster, answering MPs’ questions on inflation and financial regulation.

One inquisitor, no doubt hoping to spark outrage at how out of touch the Bank of England governor is, lobbed King a question on how much the jobseekers’ allowance was.

“For someone over 25, it’s about £65 a week,” King replied swiftly.

The precise figure is £65.45 a week, Labour MP George Mudie sniffily replied, doubtless disappointed that King was too well briefed to be caught on the hop.

The MP went on to point out that King earns more in one week (£5,000) than jobseekers do in a year (£3,000), questioning his ability to understand what was going on in the real economy.

Picking on King’s pay was something of a low blow – if the abilities of every witness were to be called into question by MPs simply on the basis of pay, there would be virtually no one left for them to grill.

King defended the bank’s record on financial regulation and fielded a series of questions on Britain’s soaring cost of living, which is running at double the government’s target of 2 per cent.

It would return to target, he insisted, but it was impossible to say when.

The governor can congratulate himself that he got one figure right – now he just needs to work on that inflation rate.

Fiona Walsh writes for the Guardiannewspaper in London