Estimates of a television audience of 2.5 billion is already being mentioned, but worldwide figures are notoriously difficult to estimate. Forty five broadcasters have already requested a feed from the BBC's cameras in Westminster Abbey and along the funeral route. and the BBC will charge them for the coverage "at normal news rates", according to a spokeswoman.
The BBC's coverage will be led by David Dimbleby, with Tom Fleming - the voice of countless Remembrance Day ceremonies - commentating on the service.
In the biggest outside broadcast operation ever undertaken, 100 cameras and 300 technicians will cover the funeral in a simulcast for BBC1 and BBC2. BBC World, the corporation's international channel, will broadcast to a further 187 countries. All five national radio stations will merge with local radio in a programme broadcast by Radio 4's James Naughtie.
Both the BBC and ITN will have cameras inside Westminster Abbey. ITN, which is also supplying other national broadcasters, will have 19 cameras inside the Abbey and 50 covering the route.
ITN's coverage will be led by Trevor McDonald with Jon Suchet providing the formal commentary along the route and inside the Abbey. ITN and the BBC are supplying pictures to the two giant screens in Hyde Park for the crowds who cannot get to the funeral route.
BBC and ITN journalists will account for just a fraction of the number covering the funeral. The big three American networks, CNN, NBC and ABC have been broadcasting their nightly news reports from London all week and have brought an estimated 150 staff into London to provide coverage.
NBC has been trying to sign up Tina Brown, British editor of the New Yorker to contribute to its coverage which will be led by anchorman Tom Brokaw. ABC has the doyenne of American TV news Barbara Walters and CBS will use Dan Rather. CNN, which believes its pictures have the potential to reach 500 million people, will use Bernard Shaw, the anchorman made famous by the Gulf War. The Foreign Press Association has registered 300 new journalists in London to cover the funeral, but believes thousands more have not registered.
The total global audience is predicted to dwarf all previous events of this magnitude. Ironically, the wedding of Prince Charles and Diana in 1981 captured a then record 700 million viewers.
As records go however, the estimated crowd of 2 million that is expected in central London on Saturday will come nowhere the 10 million Iranians - 20 per cent of the population - who gathered at the funeral of their supreme leader Ayatollah Ruhollah Khomeini in 1989.
The BBC is also making money by selling the overseas rights to the Princess's famous Panorama interview and the Heart of the Matter programme: "Diary of a Princess", when she went to Angola to highlight the problem of landmines.
It is also selling on footage of the Princess from its library and the rights to A People's Princess, the tribute to Diana shown on Sunday night.
TV's top draws
Winston Churchill's funeral (1965) - 350 million (Europe)
Wedding of Charles and Diana (1981) - 700 million
3 Tenors Concert (1990) - 800 million
Superbowl (1993) -
3 Tenors and World Cup Final (1994) - 1.4 billion
Opening Ceremony of the Olympics (1996) -3.5 billionReuse content