Charting success: The Top 40 has become an institution

Among the guests at the launch of the link-up were teenage chart-topper Craig David and teen favourites Steps

Corporation guidelines put restrictions on the use of advertising, but the BBC insisted it would not affect their coverage.

The weekly Top 40 rundown on Radio 1, hosted by Mark Goodier, commands a regular audience of 3.5 million in its Sunday evening slot - more than a quarter of all UK radio listeners at that time.

Goodier selling shares

As a result of the deal, Goodier is selling his shares in Worldpop to avoid a clash of interests.

His production company, Wise Buddha, cureently has a holding in Worldpop.

A statement from Wise Buddha said: "Following careful consideration of his options, Mark Goodier will shortly endeavour to dispose of the shares held by Wise Buddha Ltd, a company which he controls, in Worldpop Ltd."

Worldpop auims to be the "global pop network"

A spokesman for the BBC's top 40 chart show said the deal was "inevitable in an ever more competitive world".

He added: "It is entirely a matter for the rights holders. No programme on the BBC's public services is sponsored and no programme on the BBC's public services will be sponsored as a result of the deal."

He pointed out that it would be no different to coverage of sporting events such as football's FA Carling Premiership or cricket's NatWest Trophy - with two verbal credits allowed per show.

Bad hair day: Peter Powell on Top of the Pops

Peter Powell, who presented Top of The Pops in his BBC career, called the deal "wild".

"I dunderstand the excitement of purchasing a record, and I understand showbiz," he said.

He added he wanted Worldpop to become "the global pop network".

Part of British culture

The singles charts have been a part of British culture for nearly half a century.

The first number one single was Al Martino's Here In My Heart, which topped a chart of 15 records run by music magazine the New Musical Express.

It was a Top 12 chart - but there were 15 records in it as some positions were tied.

Westlife's poppy tunes earned them a record

Since then it has been a coveted prize, with holders of the top spot guaranteed maximum publicity.

When Irish pop act Westlife recently became the first act to debut at number one with their first five singles, they reportedly blew �10,000 on a night of celebration in New York.

In recent years chart battles between Blur and Oasis, as well as former Spice Girl bandmates Geri Halliwell and Emma Bunton were featured in national newspapers and on TV news bulletins.

But they all have a long way to go to top the record 17 chart-topping singles achieved by The Beatles and Elvis Presley or the 65 top 20 hits enjoyed by Cliff Richard.

These days, the longevity of the average chart single is much shorter, as the pattern amongst the record-buying public changes.