London must not waste an opportunity to advance the Olympic ideals by encouraging more young people to play sport, Jacques Rogge, president of the International Olympic Committee (IOC), said last night. He urged Britain to heed its “great responsibility” in hosting the 2012 Games by building on Beijing's successes to create a more active and healthy nation.

“Host cities have been selected because their people and government have shown they have a passion for creating a positive legacy beyond the Games,” he said in a speech to the Royal Society of Arts, Manufactures and Commerce in London. “It is a great responsibility. When the Olympic flag is handed from one host city to the next at the closing ceremony, that city begins creating its own chapter of Olympic history.”

Evoking the ideals of Pierre de Courbertin, the modern Olympics founder who was deeply influenced by British sport after his first visit in 1883 as a 20-year-old, Rogge said legacy “means more than buildings”.

“It means the lasting way the Games give people new opportunities,” he said. “I believe - as did De Coubertin - that catching the sports bug simply helps you cope with life better. It encourages you to value yourself, and your body. It equips you for learning, and improves your ability to think and create ...We know that investing in organised sport can help combat obesity, social isolation and encourage a healthy society.”

Rogge said that he was encouraged by the efforts of London organisers to put culture, education and a connection with the public at the heart of the 2012 Games. And he maintained that the global problem of youth obesity made the Olympics more relevant than ever.

He and other IOC members will want 2012 organisers to demonstrate how they will put these ideals into practice - of particular interest will be Boris Johnson's Olympics youth legacy plan to be published in the new year.

The London Mayor told Olympic leaders at an official Beijing debrief in London yesterday that he appreciated the values of “the five hoops” but - his amusings aside - it is still unclear how he will translate them to the violent and underprivileged reality of many young Londoners.

Rogge has made it a theme of the latter years of his presidency - he will stand for another four-year term next year - to engage with young people as the Olympics risks ageing with its audience. The Youth Olympics, to be hosted in Singapore in 2010, is the first event to be created by the IOC since the first winter Games in 1924.