The British art world should be supported by “proper legal muscle” to help it hold on to precious paintings, the director of the Art Fund has said, as it emerges £300 million of art has been sold abroad in the last five years.

Stephen Deuchar has argued more should be done to help institutions acquire works of art for the nation, in a process of export licensing he claims offers “avoidable loopholes” for those who do not choose to play along.

Those running the system, he said, should listen to “new ideas” to compel overseas buyers to give newly-acquired works up to the nation if funds can be raised to compensate them.

The current system of export licensing allows the Department for Culture, Media and Sport to put a bar on works going overseas immediately, offering public institutions a chance to match the amount paid for it.