By Chris Heard BBC News Online entertainment staff

For half a century, millions of British music lovers have enriched their lives - and countless artists' bank accounts - by the simple act of buying a single.

From scratchy 78 and 45rpm vinyl records through to shiny silver CDs, the single has provided aural joy and instant gratification for generations.

Our ongoing love affair with the three-minute pop record is marked on Thursday as the UK singles chart celebrates its golden anniversary.

But as the champagne goes on ice, sales figures published this week have sounded a warning about the declining state of the market.

Gambaccini says the music industry needs to embrace the internet

Demise

The number of singles sold in the UK is at its lowest point for at least 10 years, according to trade body the British Phonographic Institute (BPI).

Singles sales have dropped more than 14% in the last 12 months, and the 54 million singles bought in the last 12 months is nine million fewer than the previous year.

And as downloading songs from the internet becomes ever more common, some industry-watchers are predicting a long-term demise in singles sales.

Chart expert Paul Gambaccini thinks the music industry needs to pay greater attention to the impact of new technologies.

Internet

Paul, who is chronicling the singles chart's 50 years on BBC Radio Two, warned: "The record business has been destroying itself for several years and it shows every sign of continuing to do so.

"It hasn't made any accommodation with the internet which is clearly the delivery vehicle of choice for young people.

The Spice Girls are among the UK's biggest single sellers

"The record companies haven't come up with an alternative to piracy.

"Five years from now we should have a chart that incorporates - and indeed is downloaded by - internet hits from around the world."

Paul said the charts remained "extremely accurate" in measuring singles sales, which amounted to about 60m last year.

"The problem is that what they're measuring isn't as important as it used to be," he said.

"With the concentration of non-album artists - dance and matinee-idol television personalities - singles by album artists are no longer doing as well as they used to."

Cyclical

However, Darren Haynes, of The Official UK Charts Company, insists it is not time to bury the charts just yet.

We have seen some of the biggest selling singles out there with million-selling artists like Will Young and Gareth Gates, and sales will pick up again

Darren Haynes The Official UK Charts Company

"The single is certainly not dead," he says.

"Music sales are cyclical and it doesn't mean it's the end of the industry. It's slowing down quarter on quarter but overall it's buoyant.

"We have seen some of the biggest selling singles out there with million-selling artists like Will Young and Gareth Gates, and sales will pick up again."

The peak years for singles sales were the late 1970s and - exceptionally - 1997.

Mull of Kintyre by Paul McCartney's Wings became the UK's first two million-selling single in December 1977.

Other million sellers from the era included the John Travolta-Olivia Newton John singles Summer Nights and You're The One That I Want from the film Grease, and Boney M's Rivers of Babylon and Mary's Boy Child.

Success

By far the biggest selling single of all time was Elton John's reworked Candle In The Wind, his 1997 tribute to Diana, Princess Of Wales, following her death.

It moved 5.34 million copies in the UK - and 33 million around the world.

The song's success helped to push singles sales for the year to a record 87 million.

At its late 1990s height the singles market was worth �140m a year, but has been in decline ever since.

Just over 12 million singles were sold between July and September this year - the lowest total for the period since quarterly figures were first collated in 1976.

The British music industry is worth �5 billion a year, with music activities generating the equivalent of 125,000 full-time jobs in the UK, according to the National Music Council .

The BPI says retail spending on music in 2001 topped �2.1bn, generating �300m in VAT.

Annual album sales last year reached an all-time high of 226 million.