For those who grew up with the voice of David Coleman as their soundtrack to great moments in British sport, an Olympics without the BBC is inconceivable.

Followers of London 2012, however, will gather not only round their televisions to witness seminal episodes in Olympic and Paralympic history but also mobile phones, computers and a national network of interactive outdoor screens. The year of analogue switch-off in Britain, 2012 offers the first truly digital Games. As the domestic rights holder, the BBC is in an enviable position to exploit this convergence.

Roger Mosey, who started this week as the BBC's director of London 2012, has the highest ambitions for the coverage in 2012 and the three-year build-up to the opening ceremony on July 27. “We would ideally like to cover every single moment of every sport through online, mobile, interactive TV and the main channels,” he said. “The Olympics, whenever and wherever, literally all round the UK.”

The Olympics still delivers unparalleled audiences. The BBC broadcast nearly 2,500 hours of the Beijing Games last year and, despite the time difference, 42million people - or two thirds of the population - watched at least 15 minutes. That figure will rise hugely for an Olympics on home soil. “There is no other event that is going to get more than 45 million people watching it, with the exception of England in the World Cup final - we can dream, can't we?” Mr Mosey said.

This is perversely ominous for the BBC. Given the fragmentation of media across emerging distribution channels, such as YouTube, the London Olympics could be the last mass moment in terrestrial broadcasting history. Furthermore, the International Olympic Committee (IOC) could sell the 2014 and 2016 Games to a pay-TV operator to squeeze more money out of the rights. It halted talks with the European Broadcasting Union, which paid $746 million for the 2010 and 2012 Games on behalf of its state-backed members, to negotiate directly with broadcasters in each country. It has already sold the Italian rights to pay-TV stations owned by News Corporation, the parent company of The Times.

If a pay-TV company in Britain agreed to put the Olympics on a free and universally accessible channel and satisfied the IOC's requirement of 200 hours of coverage, the BBC could lose. It is a scenario that goes to the heart of the continuing debate over the list of “crown jewel” sports events that by statute must be free-to-air.

Mr Mosey is confident that the BBC, which has broadcast every Games since 1948, will prevail. He said: “It would be really depressing, having got to mass involvement, to reduce it to pay or niche. National moments have an intangible value. They are the core of what viewers expect from public service broadcasting, and the 2012 Olympics will be a fantastic showcase.”

London 2012 is not a BBC production, but the public will view it as such. Mr Mosey's unit may have only half a dozen members now, but by 2012 there will be hundreds, if not thousands, of BBC staff working on the Games. He appreciates that the BBC has an institutional vested interest in the success of the Games. “It's Britain's biggest moment in the international spotlight and, as the British Broadcasting Corporation, we would want them to succeed, obviously,” he said.

Much of that judgment will be made during the opening ceremony, which can make or break a Games and a nation's image. The BBC will have some input, but it is the London 2012 Organising Committee's gig.

“It's a one-off opportunity to show Britain to the biggest audience it will ever have,” Mr Mosey said. “Deciding what we show is going to be critical.”

The Games will produce classic moments to live long in the memory. Whether viewers remember how they saw them is another matter.

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