Britain is “motoring ahead” a gleeful George Osborne declared in the summer after buoyant GDP figures, and is poised to be the fastest growing major economy this year. But, as a measure of our success as a nation, is that what really counts?

For the furious protesters outside the Conservative conference in Manchester, screaming abuse – and occasionally spitting – at anyone walking through security, the answer was clearly “no”.

Inside the venue, the worth of GDP statistics was explored at a Guardian fringe event, sponsored by British Academy, to consider whether it is time to target measures of happiness and wellbeing, rather than raw economic data alone.

Since 2012, the Office of National Statistics (ONS) has been compiling such measures, prompted by a £2m cheque from David Cameron, the first major politician to pose the happiness question.

Long before reaching No10, Cameron argued “there’s more to life than money and it’s time we focused not just on GDP but on GWB – general wellbeing”.

The then future prime minister described improving our surroundings, culture and relationships as “the central political challenge of our times”.

Last month, the third ONS wellbeing survey told us that people in Fermanagh and Omagh rate themselves the cheeriest – while those in Dundee, Lincolnshire and Glasgow are the most glum.

Fermanagh and Omagh residents attributed their high happiness score – 8.3 out of 10 – to a relaxed lifestyle and face-to-face time with family and friends, instead of an obsession with social media.

The results were reported seriously, in particular the ONS’s conclusion that the gap between those satisfied with their lives and those who are not is growing.

But, it was a very different reception inside the conference centre, where the first speakers – in the absence of others delayed by that strict security – were mostly sceptical.

For Nigel Keohane, director of research at the Social Market Foundation, a centrist think-tank, the so-called happiness index is both unnecessary and worrying. He suggested policymakers are already on the right track, and argued there is a strong correlation between higher GDP and gains, including longer lives and lower infant mortality.

Keohane also warned of straying into “dead end” policy areas, with impossible aims. “It’s not as if we are going to try to make people altruistic,” he said.

“I’m very concerned about these subjective measures around happiness and wellbeing determining policy,” he added, insisting it was better to stick with hard facts and objective data.

But that criticism was nothing next to the rebuttal from Chris Snowdon, director of lifestyle economics at the free-market Institute for Economic Affairs, who was very unhappy indeed.

Snowdon argued happiness studies are a “bit of fun”, but taught us nothing because “every single conclusion you can glean is the bleeding obvious”. He illustrated this by pointing to international studies, which show that people in rich countries were happier than those in poor countries, and that poorer nations were more content if they had “nice weather”.

At home, he said, the index had risen just 0.2% in three years, because almost everybody described themselves as “a seven or eight out of 10” and similar measures all the way back to 1950 showed little change.

The conclusions were either things the government can’t change – such as the weather, belief in God, marriage, parenthood or sickness – or was already trying to – prosperity, jobs, fear of crime and bad education.

And, on the index, he said: “I will bet anybody a pound to a pork scratching that it never goes below seven and it never goes above eight. It’s a waste of £2m.”

Praise for this view came from the floor, through Edward Belsey, a Conservative councillor in mid-Sussex, with responsibility for health and wellbeing.

“You have lifted my wellbeing index by several points because I think it’s total crap,” he told Snowdon.

There was some support for the index, however. Phil Anderson, chairman of Conservatives in Thurrock – judged, in 2012, “the most miserable place in England” – described Snowdon’s tour-de-force as “ill-informed, self-contradictory bullshit” .

For Anderson, GDP growth and its focus on material consumption is “unsustainable in its current model”.

Instead, Anderson insisted happiness studies give government useful insight into “heavily contested policy areas”, such as which relationship structures to support. He referenced studies which showed contentment rises with a stable marriage, rather than co-habitation.

Anderson said: “This starts to tell us some really useful things, that promoting marriage as a desirable relational structure … is likely to promote public wellbeing.”

Back on the platform, the newly-arrived Dame Jil Matheson, a former national statistician who began the ONS’s work on wellbeing, was defensive.

She admitted the whole subject made her “twitchy” – because of its “fluffiness” – and insisted: “There is no such thing as an official happiness index – and I don’t think there should be.”

In fact, the ONS had identified “10 domains”, from talking to many thousands of people up and down the country, and was also measuring both anxiety and whether people’s lives were “worthwhile”.

A defiant Matheson said: “There is a hell of a lot that matters to people and to policymakers that is not measured by the traditional economic indicators.

“These are really important indicators that tell us how people are experiencing their lives. They put people at the heart of measurement and – hopefully – decision-making.”

It was also important to remember that it was “early days” in the process, which would be adapted and improved in future years, she said.

For Juliet Michaelson, associate director for wellbeing at the New Economics Foundation, and the author ofWellbeing and Beyond, the key was getting away from an obsession with economic output.

“The problem with our growth-led mindset is that where there are trade-offs, and of course there are many, growth always trumps everything else,” she said.

“[Wellbeing measurement] brings a distinctive human perspective and has new things to say for people interested in thinking about policy.”

Can wellbeing usurp economic indications of success? - sponsored by British Academy – at the Conservative party conference 2015 on 6 October.

The panel:

Chair: David Brindle, public services editor, the Guardian

Christopher Snowdon, director of lifestyle economics, Institute of Economic Affaiars

Dame Jil Matheson, former national statistician

Juliet Michaelson, associate director of wellbeing, New Economics Foundation

Nigel Keohane, director of research, Social Market Foundation