By Mike McCarthy, North of England Correspondent
Publicly owned works of art worth hundreds of millions of pounds are lying unseen in council vaults around the country, a Sky News investigation has revealed.
Freedom of Information requests to local authorities reveal many simply don't know how many pieces they have or what their value might be.
Some of it is uninsured and only a fraction has been on display in the past 10 years. One council said more than 90% had never been on public display.
Now there are calls for authorities facing financial cutbacks to sell some pieces to raise much needed capital.
Respected art critic Rachel Campbell Johnston called on councils to sell pieces which rarely, if ever, go on show.
Only a fraction of the art and artefacts have ever been on public display"These works are lying around, unseen, in store rooms, gathering dust, costing money. Flog them off! Make the most of them and let's hope that somebody somewhere can actually enjoy them," she said.
Sky News asked 10 authorities from across England to reveal what percentage of pieces were on public display, the total insurance value, and how many pieces have never been on public display.
Leeds City Council said it had no recorded information on how much of its collection of artworks (insurance value £150m) was currently on display.
Birmingham City Council's valuation was £235m but it refused to reveal which were the most valuable pieces in storage.
Liverpool and Bristol said their valuations were confidential.
There are calls for some authorities to sell their collectionsManchester said the valuation for local authority artworks was £371m but along with Nottingham and Southampton it refused to allow Sky News access to film items in storage.
Bristol originally told us it couldn't say what percentage of it's collection was on display but eventually revealed that it was 9%. Sheffield put the figure at 5%.
Newcastle, which holds 10,000 costumes and textile pieces alone, currently has just 3% of items on public display.
Tyne and Wear Museums and Archives said that large numbers of the city's art collection was rotated or loaned to other museums and that many items were held for study purposes only.
Bradford Council, along with many others is cutting spending on frontline services due to Government spending restrictions. Some councillors on the authority have questioned whether the council should be art custodians at all.
Liberal Democrat Jeanette Sunderland said: "One of the assets we have is a seriously underused, undervalued and underinsured art collection worth millions which nobody sees.
"I think it's right that councillors challenge the authority on what it is spending it's money on."
But Labour councillor Susan Hinchcliffe said that the city had held its collection for about 130 years.
She said: "It's been amassed by Bradfordians over all that time for the enjoyment of people in Bradford and I don't think this generation should sell-out just for a short term fix which is actually not going to solve a great deal."