LONDON.- The National Portrait Gallery hopes to acquire for the nation Marc Quinn's 'Blood Head' - it would be the only cast of Self to join a British public collection.

The National Portrait Gallery is hoping to acquire a self-portrait cast of artist Marc Quinn's head made in 2006 from his own blood and then frozen. In an appeal kick-started by The Art Fund, the UK's leading independent art charity - which has given £100,000 towards the purchase - the Gallery has until December 31 in which to raise a total amount of £350,000.

Unconventional, innovative and challenging, the 'blood head' known as Self is one of Quinn's most important and influential works, one which has become an enduring image of the Brit Art movement. The first 'blood head' was made in 1991 and shown in the Royal Academy's Sensation exhibition. Since then the artist has made a new cast every five years, documenting his own transformation and ageing. The three earlier blood heads are all in collections overseas. The Gallery wants to display the latest in the series in London, as a key work in its contemporary collection and as a way of engaging with issues of representation of the human figure in contemporary culture. The Gallery has an extensive collection of artists' self-portraits made over the past 500 years.

The work is designed so that it can be melted, recast and refrozen when it has to be moved. Because it is the fourth in the series, extensive experience exists in the care, conservation and display of such media and the Gallery has examined the technical issues thoroughly.

Self is on offer to the Gallery, through the White Cube Gallery, at a special price of £350,000. The Art Fund has generously offered to grant £100,000 and the Gallery has found £50,000 from its own resources. The Gallery needs to raise the remaining £200,000.

Emerging from the Young British Artists movement, Marc Quinn is an artist whose work raises many questions about identity and the nature of portraiture, questions which go close to the heart of the work of the National Portrait Gallery. He is already represented in the Collection by his DNA portrait of the Nobel-prize-winning Human Genome scientist, Sir John Sulston, commissioned by the Gallery, in collaboration with the Wellcome Foundation, in 2001.

Sandy Nairne, Director of the National Portrait Gallery, London, says: 'Marc Quinn's Self is a work of international significance - a brilliant and poignant extension to the genre of self-portraiture.'

David Barrie, Director of The Art Fund, the UK's leading independent art charity, says: 'One of the star exhibits at Sensation, Self confirmed Marc Quinn's reputation as one of the most innovative artists of his generation. This extraordinary self-portrait belongs in the National Portrait Gallery's collection, and I hope that others will follow our lead in showing their support for this powerful work.'