Portishead are to donate the proceeds from a new track called Chasing the Tear to Amnesty International, the band have announced.

The release coincides with Amnesty's Human Rights Day on 10 December, the anniversary of the 1948 Universal Declaration of Human Rights.

The song can be downloaded now from their official website.

"It's very exciting for Amnesty to have such generosity from the band," said Chloe Baird-Murray from the charity.

She added: "It's not just a Christmas track, it's something that can last.

"I think it's a departure from where they've been working, really going into a very upbeat and exciting track, but still with the amazing vocals

"We think the track's fantastic."

It is not thought that Chasing the Tear is the first of a new collection of songs.

However, Geoff Barrow told 6 Music in September that Portishead are back in the studio working on new material, and that they hope to release their fourth album by the end of 2010.