UK museums get 100 million visits per year - many in London

The Institute for Public Policy Research said it would be a "symbolic statement of continued and growing commitment "to the whole country".

The institute's report suggested museum attendance outside London was half that of the capital's.

The report said there had to be more effort to encourage arts participation.

The report said London was so much higher than the rest of the country because there were many more artistic venues in the capital.

The institute also said private sponsorship of the arts should be aimed at "extending access and participation rather than seeing such support simply as part of an approach to brand marketing".

Ian Kearns, the institute's assistant director, said evidence of art's use in rehabilitating prisoners and helping mental patients showed art was not a luxury.

"Assessing the value of the arts is not like evaluating hip operations or manufacturing output but the best way for the arts to compete for funding is to show evidence of their social benefit," he said.