A pounds 25m art gift to the nation ... with strings attached

One of the richest art bequests of the century has been promised to the nation - but with the unprecedented condition that it will be withdrawn if the government of the day reneges on its funding promises.

Paintings will also be immediately removed from any museum or gallery that decides to charge the public for admission.

Sir Denis Mahon, 86, the art historian, former trustee of the National Gallery and tireless campaigner for the arts, will announce today that he is to bequeath 61 works from his collection of Italian baroque masterpieces to the National Art Collections Fund. They are estimated to be worth pounds 25m.

But Sir Denis, a member of the Guinness Mahon banking family, will embarrass the Government and indeed future governments by declaring that he will withdraw his bequest if, in his view, the Government should at any time "fall short of fulfilling its various commitments in support of public collecting through the UK for the benefit of the nation in perpetuity". It is the first time an art bequest of this magnitude has come accompanied by such a stringent political condition. The 17th- century Italian masterpieces include Guercino's Elijah fed by Ravens, Lodovico Carracci's Agony in the Garden, and Guido Reni's Rape of Europa.

Unusually, Sir Denis has ensured that legal ownership of the paintings will remain with the National Art Collections Fund and he has asked that the fund, an independent charity, should at once withdraw any works deposited if the gallery or museum concerned should decide to sell off any item from its permanent collection.

He is also stipulating that his paintings should be withdrawn from any gallery or museum that decides to charge admission, an option being widely considered by many institutions.

Twenty-six paintings are to be placed with the National Gallery, 12 with the Ashmolean Museum in Oxford, six with the Fitzwilliam in Cambridge, five with Birmingham Museum and Arts Gallery, three with the Walker Art Gallery in Liverpool, one with Temple Newsam House in Leeds and eight with the National Gallery of Scotland. The bequest also gives the National Gallery discretion to loan some works to the National Museum and Gallery of Wales in Cardiff. None at present charges for admission, but all have been affected by falling government resources.

Sir Denis said: "I feel passionately that the Government must not persist in its policy of progressively cutting grants in aid to museums and galleries. The figures for 1997-98 [announced last week] represent a significant cut in the value of central government funding for our national art collection, and what is most alarming is the downward trend which is set to continue in subsequent years.

"I am a firm believer in the principle of partnership between the public and private sectors, but the principle becomes meaningless if it is not respected by the Government."