A body of previously unseen work by Lucian Freud has been acquired for the nation from the estate of Lucian Freud through the Acceptance in Lieu Scheme. Containing 47 sketchbooks and additional drawings, plus a collection of 162 childhood drawings and a collection of letters from Lucian Freud, the acceptance settled £2,940,000 of tax.

Dr Nicholas Cullinan, director of the National Portrait Gallery, London, said: “The gallery has a strong association with Lucian Freud by virtue both of its permanent collection holdings and the highly successful 2012 Lucian Freud Portraits exhibition. This archive, which will in due course be made available to the public, will be a vital source of reference for anyone interested in the life and work of the artist or in portraiture in general.”

Culture minister Ed Vaizey added: “This rare collection of Lucian Freud drawings and letters provides a fascinating glimpse into the work of one of our most pioneering artists. Bringing these never seen before treasures into public collections means that everyone can enjoy and see the early beginnings that shaped his most celebrated work.”

Administered by Arts Council England, the process enables taxpayers to pay inheritance tax by transferring important works of art and other important heritage objects into public ownership. In the last five years the scheme has bought objects to the value of £150m into public collections.

Sir Peter Bazalgette, chair of Arts Council England, said: “The Acceptance in Lieu scheme has been enriching our museums and galleries for over a century, as does this latest offer from Lucian Freud’s estate. This fascinating archive, which has never been exhibited before, offers us a real insight into the life of one of Britain’s most compelling and influential artists.”

The National Portrait Gallery hopes to display a selection of items from the archive in early summer 2016