Tower Hamlets mayor's resolve to sell Draped Seated Woman draws censure from Danny Boyle and warnings from art experts

Experts are warning of a wave of public art sales by local authorities after Tower Hamlets agreed to sell a Henry Moore statue, donated by the artist on the understanding it would be left permanently on open-air display for the enjoyment of people in a socially deprived area of London.

Lutfur Rahman, the independent mayor of the borough, overruled the recommendation of his councillors that Draped Seated Woman– which could fetch up to £20m – should not be sold. Rushanara Ali, the Labour MP for Bethnal Green and Bow, said Rahman was "going against the desires of the over 1,500 people who have signed the petition [against the sale] in just a few days".

The decision was also condemned by Danny Boyle, a Tower Hamlets resident and director of the opening ceremony for the 2012 Olympics. "The value of art is diminished by being monetarised," he said on Wednesday night. "The Moore sculpture defies all prejudice in people's minds about one of London's poorest boroughs. That alone makes it priceless to every resident."

Rahman, however, said the money raised would ease the £100m budget cut that Tower Hamlets – home to some of the worst deprivation in Britain – will face over the next three years.

The Moore is the latest in a growing list of sales of public artworks by councils. Last year, Bolton Council sold seven works of art, including two etchings by Picasso and a painting by John Everett Millais, and Gloucester city council approved plans to sell 14 works of art valued at £381,000. In the same year, Newcastle City Council put £270,000 of publicly-funded artwork for sale on eBay and Leicestershire County Council made more than £160,000 after selling off some of its art collection.

Ian Leith, founder and deputy chairman of the Public Monuments and Sculpture Association said other councils might now be tempted to sell off their public artwork. "We fear that this is the beginning of local authorities wanting to realise the assets they have in their public sculptures," he said. "But the danger is that we won't find out about these sales: There is no national audit of public art in England and no at-risk list.

"Many public sculptures are not listed at all. Indoor art, art in private gardens and war memorials are audited but no one is responsible for outdoor art."

According to English Heritage, less than 15% of the estimated 10,000 pieces of sculpture in public spaces, including war memorials, are included on their register of listed buildings.

Leith said: "We are calling for local authorities to make audits of their public art and put them online. Ratepayers should ask councils what art they have and where the public record is. Every council has this information; it's just buried deep in their planning departments. They need to excavate it and get it online."

An audit of public art was welcomed by English Heritage and by the Twentieth Century Society, which has petitioned Camden council to prevent the sale on 14 November of a giant bronze statue by Sir Eduardo Paolozzi that has been on public display in central London for 25 years. The sculpture is privately owned but was designed to stand on the pavement in front of a private office at 34-36 High Holborn.

"The Twentieth Century Society is urging Camden council to take immediate action to ensure this important work of modern sculpture remains visible to the public," said Catherine Croft, director of the society.

"The self-portrait takes up a third of the facade, which is completely designed around it. This is a conservation area and its removal would be an act of substantial demolition. It might be technically a private piece of art but it's clearly a public piece of art which should not be sold off."

Counsellor Flick Rea, chair of the Local Government Association's culture, tourism and sport board, also said that more public artwork could be sold. "Councils are facing unprecedented cuts to funding and are having to make extremely difficult decisions as they seek to keep providing vital services such as caring for the elderly, protecting children, collecting bins and filling potholes," she said.

"When considering the sale of art, a council will always take into account the views of local residents and explore all the options on the table to try and reach a solution which best suits the circumstances."

But, Rea added, a national audit of public artworks would be unlikely to be cost-effective. "Ethical and practical guidance for councils regarding the sale of art already exists and was drawn up jointly by the LGA and Museums Association," she said. "Proposals to insist they also provide a comprehensive public list detailing every piece of art they own would have to demonstrate a meaningful benefit which outweighed the extra burden."

Andrew Shoben, professor of public art at Goldsmiths, University of London, said that a national audit would be of limited use.

"Having a list of all public artworks would be great but a large number of these works are what is known as 'orphaned' – that is, no one knows who they're by or who owns them," he said.

"Councils often don't even know what artworks they have in their area," he said. "What a national audit would show up is how many unloved, unserved and uncleaned public artworks there are in this country."