Something pretty amazing must have been happening in Mexico in the mid 60s. Perhaps it was the summer of love that got to them. Of course they knew they had the Olympic Games and the Football World Cup on the way – maybe that was the trigger for a creative leap forward – especially in graphic design. I need to find out more and I now know where to go.

Last night was the opening of a remarkable exhibition of Olympic Posters at the Museum of Childhood in London’s Bethnal Green. The Museum is a branch of the V & A and they have one of the best collections of Olympic posters. To mark the year of handover from Beijing to London they’ve created the most exhaustive and illuminating of exhibitions. Just about everything is there – from formal proclamations of the early British pioneers of the Olympian Games in Much Wenlock and the Cotswolds in the mid 19th century through to the current crop of posters from Beijing and some glimpses into the future in London.

I'm wondering if I’ve got the 'sell' right here? Is the history of posters, and Olympic posters at that, a rather 'train-spotting' branch of cultural nerdism? Absolutely not.

The exhibition works on many strata. The art itself is eloquent and some of it simply brilliant. The gallery cleverly traces the history of the Games and the political and cultural context – from the classical illusions of 1920s Stockholm and Nazi Germany in 1936 through to the brutalism of Moscow in 1980 and commercialism of more recent Atlanta. It prompts you to question what each games wanted to communicate in its official poster. Lake Placid clearly just wanted the world to know where on the planet it is – a, map, a town a skier – enough said.

The Munich Games made many a statement in 1972 through its posters and many other forms of architecture and design. The official poster is radical and spectacular - but beyond that the German organisers went further by commissioning a raft of the most dynamic and thoughtful contemporary artists to create their own unique poster images to reflect the spirit of the games. The collection – all on show in the exhibition – bares witness to the boldness and risk-taking culture that must have imbued the games. Barcelona (1992), as you’d expect from such a cultured city, makes a great artistic splash too.

All of this, however, pales into insignificance, for me, when compared with the Mexico games of 1968. As you walk around the gallery in Bethnal Green you take a historical amble through every games and each era reflected through it’s posters. And then there’s an artistic electric shock as you come to Mexico. Even the athletes on the track must have been stopped in their tracks when they saw the graphic images, the designs and the logos that represented the Mexico Games of 1968.

In part they are so of their time - so '1960s' – geometric swirls and psychedelic shades – but so much unlike anything before them – or since. They broke with the format, the shapes and protocols of just about any of the posters and designs that preceded them. I would have loved to be at the meeting when the designers first presented their ideas to the International Olympic Committee in Lausanne. And are the designs merely curios stuck in a rather freaky bit of popular history? Not a bit of it – they stand up to all comparisons. They have energy, brio and athleticism. They represent the games ability to reinvent itself and be relevant to new generations.

London 2012 doesn’t have an official poster yet. That will come after Beijing has handed us the Olympic and Paralympic flag in just three months time. But the exhibition concludes with the much talked about London 2012 brand image. It still prompts debate – and that can only be a good thing - but I have a suspicion that when this fine exhibition is re-staged in another fifty years it will be London that will take its place alongside Mexico as a design classic that broke the mould.

And I made an interesting discovery last night. In the early stages of creating the London 2012 brand, who was amongst those consulted? None other than the original designer of the Mexico 1968 logo…Lance Wyman

You can find the exhibition details at http://www.vam.ac.uk/moc/