Ms Middleton and springtime provide a measure of happiness

If only the French could rustle up some royals of their own for a wedding at Notre Dame, think how it would benefit their own struggling economy. But of course, they should have thought of that before they invented the guillotine.

How happy are you? I'm sorry to ask such a personal question, but it's a subject much on the minds of Europeans just now. With Ireland deep in crisis, Portugal and Spain approaching along the conveyor belt and now even Belgium reaching for the nerve tonic, happiness is currently in short supply in my small corner of the globe.

You might think that any politician preparing to spend millions of taxpayer money trying to gauge such an ethereal commodity while so many of his countrymen are being handed redundancy notices would be signing a political death warrant. But the British prime minister David Cameron has just proposed just such a venture, and he's deadly serious.

The Office for National Statistics has been asked to come up with a "National Wellbeing Project" that will accurately measure people's sense of well-being and give our eleleaders an accurate reflection of national mood. Denying his scheme was "airy-fairy and impractical", the PM insisted that it would measure things that cannot be calibrated by merely fumbling in the greasy till of economic prosperity - things such as contentment, health and education.

His initiative has already been dubbed by critics as more likely to end up a "misery monitor", particularly since the British, who've turned the art of whingeing into a national sport, are likely to use it to vent their feelings of frustration and despair at the parlous state of affairs.

Nonetheless, quoting the late Robert F Kennedy, Mr Cameron insisted that GDP measures everything "except what makes life worthwhile", and that the project will help us re-evaluate our priorities. Indeed, so persuasive is his case that the French president Nicolas Sarkozy of France is reportedly considering a similar initiative for his own countrymen.

Sadly for the French premier, happiness is likely to be in far greater supply in London than Paris during the coming months, for Mr Cameron has one advantage that Mr Sarkozy can only dream of: a royal wedding.

Snow may be falling, the pound may be sinking and England may have got off to a dicey old start in The Ashes, yet ever since Prince William and Kate Middleton announced their engagement last week, the country has been wearing a beatific smile.

After all, everyone loves a party, particularly since the government has announced the wedding day, April 29, is to be a public holiday. The announcement of the betrothal seems to have sent even the most hard-bitten journalists into paroxysms of simpering bonhomie - indeed, during one trawl of the TV on the day the news broke, I was able to watch the same interview with the couple on five channels simultaneously.

The cost of staging and policing the ceremony in such straitened times has understandably raised a few eyebrows in the treasury, which is no doubt why, in a sop to Republicans everywhere, the in-laws have announced that they're going to divvy up as much of the cost between them, which by some estimates will cost in excess of $20 million.

Given the disparate incomes of the two sets of parents, we can safely assume Mr and Mrs Middleton (who run a childrens' party business) will provide the cake stand while Mr and Mrs Windsor (the 245th richest couple in the land) will shoulder the rest.

Still, as Mr Cameron is keen to emphasise, it's not all about money. Apart from the undoubted monetary wealth the occasion will generate in tourism, hospitality and TV rights, it should also serve to make people forget just how grim things are.

In the meantime, Mr Sarkozy can only sit and fume. Zut alors! If only the French could rustle up some royals of their own for a wedding at Notre Dame, followed by a ticker-tape parade down the Champs Elysees, think how it would benefit their own struggling economy. But of course, they should have thought of that before they invented the guillotine.

Meanwhile, the marriage of Prince William and Kate next spring should ensure Mr Cameron's happiness index is not short of raw material. Add that to the feel-good factor likely to be provided by the London Olympic games in 2012, and it would seem that the prime minister may have one commodity that is utterly priceless in the business of politics - that of luck.

I for one can't wait to get involved in the project. In fact, I can think of a simpler way of arranging things. If only Mr Cameron could be persuaded to offer me the sum he's intending to spend on the survey, I'd single-handedly send his happiness ratings soaring through the roof.

Michael Simkins is an actor and writer based in London