A website in the US is being sued for copyright infringement after selling the Beatles back catalogue digitally -- the first time the Fab Four's treasure chest has been available to download.

The MP3 files are available on Bluebeat.com for only 25 cents US (15p) each, while all of the band's 14 studio albums -- including the remastered versions, which were released in September -- can be streamed for free. Full albums can be bought for $4.25 (£2.60). The site had started offering the band's music last week, at a price one-fifth of the cost of files from iTunes.

The songs are being sold on the site despite EMI and the Beatles' Apple Corps' persistent attempt to prevent the sale of the band's material as downloadable files.

The site Music Ally said EMI confirmed the suit had been filed at a California court.

Stuart Dredge, editor of Music Ally, had been quoted by quoted by the Daily Telegraph saying the site's continued selling of the Beatles' material was out of the ordinary. "BlueBeat is one the first download stores in the West to sell unlicensed downloads. Usually it's the pirate sites that behave like this and there have also been some similar issues with Russian and Lithuanian sites.

"But it is really strange for what had been a legal and commercial site to behave like this and get away with it for this long."

The news of the suit against Bluebeat came amid the launch on Nov. 3 of 30,000 apple-shaped USB devices which contain 14 of the remastered Beatles album as FLAC and MP3 files. They go on sale on Nov. 7 in Europe and Nov. 8 in the US, with a price tag of £200 in the UK and $279.99 in the US.