I have just returned from a week in Beijing, where I've witnessed an amazing spectacle. There is no doubt in my mind that the Olympic Games are a real catalyst for change. I have seen first-hand the power of the Games to transform a city and unify a nation, and it is humbling.

In four years' time we will all have the opportunity to participate in the 30th Olympiad of the modern era right here in London - 2012 will be a pivotal moment for our city.

This is due to the unique combination of one of the world's most recognised powers, the Olympic Movement, and perhaps the world's most dynamic and innovative city. Both represent diversity and inspiration, creativity and connectivity, leadership and hope.

On the eve of the handover, when our Mayor accepts the Olympic Flag, Visit London will launch a global advertising campaign. Two cities, one handover and the official launch of the London 2012 Olympic and Paralympic Games.

"See the World, Visit London" underpins the importance of the capital as the number one international tourist destination and, as we prepare to host the greatest sporting event on earth, demonstrates there is no other place to be than here.

Building on our city's history of success, the 2012 Games will be a once-in-a-lifetime opportunity, especially in its regeneration of east London.

The capital already welcomes more overseas tourists than any other holiday destination. However, like all industries facing uncertain economic conditions, tourism must brace itself. This is why the Olympics are a cause for celebration.

Tourism is one of the clearly deliverable legacies of the 2012 Games. Oxford Economics forecasts the potential tourism benefit is in excess of £2 billion.

This legacy will f low from an increase in visits to our city, not just from our traditional markets such as the United States and Europe but also the rapidly emerging economies of the world.

Outbound travel from countries such as China and India will create a new world of global tourism in the years to come.

It is estimated China alone will have 100 million outbound tourists by 2020. The 2012 Games are a unique opportunity to make London the number one destination for these visitors too.

The Olympics really are like no other event. They are much more than just two weeks of sport. They showcase a city and nation, its energy, its culture and its people. I have no doubt that in 2012 we will deliver an amazing experience, something Londoners will be incredibly proud of.

However, delivering the post-Games tourism legacy involves insightful planning and strategy, and investment and commitment from the private and public sector. The Olympic legacy is there for the taking.

This Sunday, as we celebrate the handover together with the amazing medal tally of our athletes in Beijing, let us all commit ourselves - whether we are in politics, business, the arts, tourism or sport - to delivering that legacy for our city and nation.