By Tom Bishop BBC News Online

Norah Jones sold 19 million copies of her debut album worldwide

In this week's Top 10, Katie Melua, Jamie Cullum and Norah Jones have charmed CD buyers while middle-of-the-road giants Daniel O'Donnell, Engelbert Humperdinck and Harry Connick Jr have lumbered back into view.

Of the few pop acts that remain in the Top 10, the mellow Zero 7 and newly-soulful Will Young sound distinctly adult. So how did every day come to sound like a dinner party?

"People like melody and quality in music, and there are a lot of good songs around right now," says Colin Martin, executive music producer for BBC Radio 2.

"During the 90s, the chart was dominated by high-energy tracks with little to appeal to a broad range of album buyers.

It's been like a bolt from the blue Stephen Graham Jazzwise magazine

"Now there is hardly anybody who will not enjoy the current albums by Katie Melua, Jamie Cullum or Lionel Richie."

Jazzwise magazine co-editor Stephen Graham traces the current jazz and middle-of-the-road (MOR) revival to pianist Diana Krall, whose album When I Look in Your Eyes was a global hit in 1999.

"Diana Krall tapped into the lucrative adult market and paved the way for Norah Jones," he says. "People liked the fact that Norah Jones was a young singer-songwriter and she had phenomenal success."

Norah Jones sold 19 million copies of her debut album Come Away With Me, including two million in the UK.

This is all about lengthy careers, rather than just making music for today Colin Martin BBC Radio 2

"That success has continued with her new album, by which time she had in turn paved the way for Jamie Cullum's �1m record deal," Mr Graham says.

Industry magazine Music Week attributes the rise in easy listening to "Des and Mel, [Michael] Parkinson and beer adverts".

Exposure on TV and radio has dramatically boosted sales, but Radio 2's Colin Martin believes the new accessibility of albums is another vital factor.

"In the past, some people may not have wanted to go to record shops to search out these artists, but now they can just pop them in their basket at a supermarket," he says.

Jamie Cullum has won a place in both the album and singles charts

Whatever the reason, people aged between 40 and 49 have been inspired to buy more albums - accounting for 19.1% of total album sales in 2002 compared with 16.5% in 2000, according to British Phonographic Industry figures.

The popularity of MOR and jazz has led to a sharp contrast between music formats, with the albums chart topped by artists who find it difficult to conquer the youth-dominated singles chart and vice versa.

The fact that Katie Melua and Jamie Cullum have already enjoyed top 20 hits may bridge that divide, however.

"Even a widely-respected jazz artist such as Courtney Pine never made it into the singles chart," says Stephen Graham. "It's been like a bolt from the blue."

Everything in music is cyclical - I can already detect a backlash Stephen Graham Jazzwise magazine

Will the appeal of mellow jazz and MOR artists continue to broaden? Colin Martin believes so.

"We continue to champion artists such as Amy Winehouse, Damien Rice and Sarah McLachlan because we believe strongly in artistic development," he says.

"They have the potential to keep getting better and better. This is all about lengthy careers, rather than just making music for today."