Fears have been raised over the future of the Warburg Institute library, the unique collection founded by a German-Jewish scholar.

The original 80,000-volume library, which included books on art history, science and astrology, was put together by Aby Warburg in the 19th century.

When the Nazis came to power, it was brought to London by the Courtauld Institute of Art founder, industrialist Samuel Courtauld.

It was then signed over by a one-page deed to the University of London in 1944, where it has since remained, in Woburn Square, and has grown to 350,000 items.

Academics voiced concern after it was revealed that the university has begun legal action to clarify the terms of the deed charging it with looking after the collection "in perpetuity". It is suggested that it has become too expensive to care for, and could be merged with another collection, or split up.

"The Warburg Institute is an emblem of the survival of civilisation in Europe's darkest hour," said Lisa Jardine, Professor of Renaissance studies at University College London. "To casually consider its usefulness today is just shocking."

An online petition calling for Aby Warburg's legacy to be preserved had been signed by more than 20,000 people by Wednesday.

A spokesperson for the university said: "At no point has it sought to challenge the deed, but it has sought guidance as to its meaning, and we look forward to the court's judgment later in the year."