So the greatest show on earth starts and the world loses all sense of perspective.

China has reportedly spent £21 billion on its Olympic Games, more than twice the amount that crippled Greece four years ago and 32 times what was spent when Los Angeles was host city in 1984.

This year’s celebration started with a memorable opening ceremony but during the three hours of lavish entertainment on Friday one thought kept popping into my mind: extravaganza or extravagant?

Providing such an awe-inspiring spectacle is, I suppose, the point of any opening ceremony; even though I find opening ceremonies for sporting events pointless and cryptic exercises.

Critics have said this ceremony’s choreography was meant to reflect China’s burgeoning status as a superpower and, in that respect, the Games have followed suit.

The success of both has been down to manpower.

About 14,000 people were involved and trained for 13 months for that opening celebration, which was watched by 840 million viewers in China and four billion on television worldwide.

Yes, the Olympic Games might be the greatest show on earth but they come at a paralysing price.

Buzz phrases like ‘Olympic legacy’ and ‘inspiration to young people’ are being bandied around gaily in London as if in some way justifying what will be a gross expense on a two-week sporting celebration in four years’ time.

The Olympic flame is ephemeral, you see, and talk of the Olympic legacy is fallacy.

The Games’ greatest asset is its ability to bring together a panoply of minority sports and provide them with a stage to showcase their intricacies to the world – for one fortnight. While the sports prove strong in unity, alone they are weak.

Of the 22 Olympic sites in Athens, for example, 21 are now either unused, derelict or unaffordable – in some cases all three.

Eight years after the Sydney Olympics, the stadiums are costing £16million per year to maintain and the authorities are yet to break even.

The Athens Olympic Stadium, which was part of the £9 billion investment that Greece’s government seriously over-committed, has been used since 2004 for concerts and other entertainment - but is very far from thriving.

The London Organising Committee is confident of not falling into the same trap as Athens because of its ambitious post-Olympic plans.

Sport can do wonderful things and can reach communities politicians cannot hope to but the notion that Britain’s disaffected youth is going to be persuaded to take up sports like archery, equestrianism, rowing, diving and fencing, most of which will return to their prohibitively expensive forms in the United Kingdom a few years after London’s candle has burnt out, is ambitious in the extreme.

Through this Olympic Games, we will continue to see sporting excellence at its most inspirational and heart-warming - but the wave of emotion will subside for another four years at the closing ceremony until the London Games begin.

The extravaganza is fun and fascinating while it lasts, but it’s the extravagance that leaves the legacy.