Metallica surprised fans at the Download music festival

It was made after the band, who formed in California in 1981, hired a therapist to help them work together better.

The album sold 418,000 in its first week on sale and is the band's first to have been made in the studio since they released Reload six years ago.

St Anger is also their first record since the departure of their longtime bassist Jason Newsted and it also includes a bonus DVD of the band playing the album's tracks live.

Its number one placing has made this album the fourth rock album in a row to top the US album charts.

Internet code

Last week, Led Zeppelin's live retrospective How the West Was Won was the top-selling album in the US.

Previously, records by Staind and Marilyn Manson had also been chart-toppers.

The number two record in this week's chart was folk-singer Jewel's latest album, 0304, while rapper 50 Cent's record Get Rich or Die Trying was in third place.

Despite the downturn in album sales in recent years, St Anger sold only a fraction less than the 435,000 copies sold of Reload in its first week in 1997.

St Anger includes a code that allows people to access exclusive tracks from the internet.

Napster case

In 2001, Metallica filed a lawsuit against the now-defunct Napster file-swapping service for allowing users to download songs without permission.

Napster later settled the case by agreeing to restrict the use of their music.

At the time, the band members said they were not against music-swapping but were against their music being made freely available without their consent and without proper remuneration.

The band made a surprise appearance at the Download festival in the UK earlier this month.