Crazy Frog topped the charts but the appeal of ringtones is fading

The trend - characterised by the incredibly popular yet infuriatingly irritating Crazy Frog - saw ringtone sales reach �177m last year.

But 2006 will see the first fall in ringtone sales, music consultancy MusicAlly says, and the industry may be worth just �78m within four years.

Subscription charges and changing technology are behind the pattern.

'Fed up'

Customers have grown tired of signing up for what they thought was a single download, but finding themselves facing hidden subscription charges, said MusicAlly spokesman Steve Myall.

"People have got fed up with being conned," he said.

The popularity of phones capable of storing hundreds of songs in their entirety has also led to falling demand for ringtones.

This means customers can transfer tunes from their computers to their mobiles and use their own music collection as ringtones, rather than buying specific snippets.

The trend will be a blow to record companies who see ringtones as an extra stream of revenue.

I Don't Feel like Dancin' by The Scissor Sisters is among the current most popular full-length downloads in the UK.

The Crazy Frog ring, created by a Swedish student, spawned a record which went to number one in the UK charts - keeping Coldplay at number two.