Last year, the Daily Telegraph exposed various instance in the last fity years where damage had occurred  to the Elgin Marbles whilst they were in the Duveen Gallery at the British Museum.
In January, a visitor to a museum in Oxford tripped & knocked over  two Qing vases.
Accidents can happen in any museum, but when they do happen it makes a mockery over any claims that the museum might make about how they should retain artefacts rater than returning them to their countries of origin, as they are better able to preserve them. This fact still applies whether or not the artefact is insured.
Now, after investigation by the Daily Telegraph, the museum in Oxford admits that these vases were not the first instance where visitors had seriously damaged artefacts in their collection.
The Daily Telegraph 
Whoops (again)! We didn’t insure £100,000 vases, admits museum
By Chris Hastings and Adam Lusher
It was perhaps the most catastrophic “Norman Wisdom moment” in the history of museums and fragile artworks, and it has just got worse.
Things seemed bad enough when a loose shoelace sent Nick Flynn tumbling down a staircase at the Fitzwilliam Museum in Cambridge. The ensuing crashlanding smashed three 300-year-old Qing Dynasty Chinese vases, (estimated value, when not in smithereens, £100,000.)
Now documents obtained by this newspaper reveal that the museum will receive nothing in compensation for the smashed vases because it failed to get them insured.
And the same papers reveal that the debacle was not the only “Norman Wisdom moment” at the museum.
In 1999 an Egyptian sarcophagus lid which had survived more than two millennia met its match in the form of a French teenager on a school exchange trip.
Attendants caught the 15-year-old trying to hide the three fragments detached by his attempt to lift it.
The limestone lid, also uninsured and estimated to be worth tens of thousands of pounds, needed extensive repair and was removed from the premises for three years.
Seven years later, Mr Flynn and his shoelace arrived. He was photographed after his fall lying amid the porcelain. The contrite 42-year-old described it as “my Norman Wisdom moment”.
Documents obtained under the Freedom of Information Act show how the museum wanted to avoid admitting the vases were not insured, with one internal e-mail recording “our wish to be reticent in response to any questions about insurance”.
After Mr Flynn’s fall, members of the public e-mailed the Fitzwilliam, with one complainant asking: “Are you fit and capable of retaining and showing ancient relics or should a more professional institution take over?”
The Fitzwilliam, which has consistently refused to discuss the vases’ value, is engaged in a painstaking attempt to glue 25 trays of porcelain fragments back together, but the work is unlikely to restore the vases to their former glory.
Independent art experts estimate that in their undamaged state the vases could have collectively been worth as much as £100,000.
The sarcophagus lid is probably worth tens of thousands of pounds, say Egyptologists. It once topped the coffin of a priest who worshipped the last native Egyptian pharaoh, Nectanebo II, who ruled from 360BC to 343BC.
Showing little respect for the Pharaoh, the priest or the weight of his 440lb sarcophagus lid, however, the French schoolboy tried to lift it.
The museum accepted £2,500 from the boy’s insurers, half the true cost of repair.
A Fitzwilliam spokesman said: “The museum’s stewardship and management of its collections meet the highest standards as affirmed by full accreditation from the Museums Libraries and Archives Council.”
The incidents may lead to questions about how artefacts are cared for in British museums.
Most British museums do not insure their collections, said Robert Read, the fine arts underwriter for Hiscox plc, an insurer of international art collections.
He said: “They have got to prioritise and they tend to spend on things like fire alarms or security guards.”
There was, however, comfort for the Fitzwilliam from the leading Egyptologist Wolfram Grajetzki, who said: “Things quite often get broken in museums. You carry an object in the stores, you drop it. It happens more often than people admit.”