The artist, who died in 2011, specified in his will that the artworks should be donated in place of inheritance tax.

BBC: Lucian Freud donates Corot and Degas works in lieu of tax

The work was secured for the nation through the Acceptance in Lieu Scheme - administered by the Museums, Libraries and Archives Council (MLA) - which enables items deemed to be of historical or artistic importance to be given in place of inheritance tax.

BBC: Portrait returns to Palace 'home'