Tate Modern could benefit from the scheme

Works by living artists, such as David Hockney, could be sold to allow the Tate to buy better or more appropriate items by the same person.

Despite Hockney's stature, the most recent of his pieces in the Tate's collection dates back to 1977.

Tate director Sir Nicholas Serota said there was not enough money to buy works which were offered to the institution.

He told The Art Newspaper: "Sometimes, we find artists are not represented by the best examples of their work, or perhaps we have two or three pieces which we are unlikely to show together because there are close in type."

The idea is still at an early stage, and Tate trustees have made no decision on whether to go ahead with it.

But the institution would only consider selling works by living artists and with their permission.

National museums are allowed to dispose of works if an item is "unsuitable for retention", which the Tate feels would allow it to sell off works to upgrade its collection.

"There would be no question of selling a Turner to buy a Hirst," Sir Nicholas added.

The Tate's collection is shared between its two galleries in London, Tate Britain and Tate Modern, as well as galleries in Liverpool and St Ives, Cornwall.