Museums need all the help they can get, warns Tate donor Mercedes Stoutzker

The philanthropist behind a major new gift to the Tate galleries has called government plans to cap tax relief for charitable donations "the wrong thing to do", warning that the price of art has led to British galleries struggling to "fill in the gaps" in their exhibitions.

Mercedes Stoutzker, who with her husband, Ian, announced a gift to the Tate yesterday of nine major works of 20th-century art, said that the arts could lend "a different dimension to people's lives" and urged the Government to encourage giving in "every way possible".

"If you look at museums in America and see how well endowed they are by private donors, you see that galleries in Britain don't have nearly so much," she told The Independent.

"Art has become so expensive nowadays. My husband and I were lucky to buy these pieces at the beginning of their life, before prices rose. For museums today to be able to afford this art is almost an impossibility. In the end what is most important in a museum is its collection."

The Soutzkers, who live in Austria, are long-standing patrons of British art. Sir Nicholas Serota, the director of the Tate, said that their gift "greatly enriched the national collection of art". He added that the Soutzkers' decision to donate had not been affected by the plans to change the law on charitable giving, but hoped their generosity would "encourage" others.

"They don't receive any tax benefit from this gift but in the current climate they were very keen to make it public because they wanted to encourage others to give works to the national collection," Sir Nicholas said.

The works, dating between 1947 and 2005, will "fill some gaps" in the Tate's collection, Sir Nicholas said.

Among the works is David Hockney's 1966 painting Saving and Loans Building, a 1947 sculpture of Lucian Freud by Jacob Epstein and a portrait by Freud himself, Girl in a Striped Nightdress. The latter, until last weekend, was on display as part of the critically acclaimed Portraits exhibition at the National Portrait Gallery.

Culture couple: The philanthropic Stoutzkers

Mercedes and Ian Stoutzker are a couple with a profound passion for British art. Their gift to the Tate represents their biggest, but by no means their first, contribution to the cultural life of the nation.

Now based in Salzburg, Austria, the pair were married in 1958, when Mercedes came to live in London from her birthplace in Tangier, Morocco. She loved art and immersed herself in the cultural life of her new home, expanding her taste and knowledge. She gradually built up a collection of works by outstanding British artists, often acquired long before they were serious contenders for Tate prizes. Today the pieces she collected represent one of the finest private collections of British 20th century art – nine key pillars of which have now been gifted to the nation.

Ian Stoutzker, a trained musician who later became a banker, shares his wife's passion and has also been a significant contributor to British music. With the violinist Yehudi Menuhin, he founded Live Music Now in 1977, which brings musicians into prisons, hospitals, special schools and community centres. Last year he gifted £500,000 to the Royal Welsh College of Music and Drama, a personal tribute to his mother Dora, who taught music in Tredegar, Blaenau Gwent. A new concert hall at the Cardiff college was named in her honour.

The Tate's director, Nicholas Serota said that their legacy of giving should encourage future philanthropists to support the arts in Britain.