In a candid submission to the Scottish Parliament committee considering The Burrell Collection (Lending And Borrowing) Bill, Dr Nicholas Penny, the director of the National Gallery in London, says moving works of art has led to several major accidents, incidents and damage to works, many of which have not come to public attention.
Dr Penny said he would be prepared to describe the incidents in confidence to a "single trustworthy individual nominated by Scottish Government" if the committee desired.
In his document, Dr Penny also appears to question the efforts by Glasgow City Council and the Burrell Trustees to alter the gift agreement of Sir William Burrell from 1944, which stipulated the works could not leave Glasgow and be shown overseas.
The submission was greeted with surprise by Glasgow Life, the organisation that runs the city's museums. One source said: "We are flabbergasted by this."
Tens of thousands of visitors see the Burrell's collections of art, antiques, tapestries, armour and sculpture every year, but the building containing the Burrell Collection in Pollok Park is in need of a major revamp, believed to cost about £40 million.
The revamp will lead to the building being closed between 2016 and 2020, and the parliamentary Bill is required to alter Sir William's deed of gift so the art can be seen by national and international audiences while it is shut.
Dr Penny wrote: "What is very often forgotten in discussions of this kind is the moral advantage and tangible (if not always immediate) benefit of a declared preference for honouring the wishes of the donor. Real concern for the future is always more persuasive in those who have a genuine feeling for the past."
He said the financial benefits of touring art collections are also "greatly exaggerated" and did not lead to any significant increase in visitors to the galleries touring the works.
He added: "There has always been much talk of 'profile raising' to palliate the mercenary motive or to compensate for a disappointing fee ... it would not be appropriate for me to say the Burrell should not engage in such an exhibition, but the interests of those encouraging it and brokering it should be examined very severely - they are not always obvious. Loans for fees are, it should be remembered, a short term fix."
Sir William Burrell did not want his art to tour abroad because he was concerned about the safety of shipping art around the world, but the Burrell Trustees and supporters of the Bill, such as Museums Galleries Scotland, believe modern air transit is much safer.
In the submission, which comes ahead of a public meeting of the Burrell Bill Committee on Monday, Dr Penny said an accident to a plane is more likely to lead to the total destruction of any work of art, more so than with ocean liners.
The director added he knew of 10 major accidents in transported art during his 27 years working in museums and galleries.
A spokesman for Glasgow Life, said: "In the last five years, Glasgow has loaned more than 400 objects to 150 venues in 12 countries and has received 1700 objects from almost 250 lenders from eight countries. There has not been a single claim as a result of damage to any of those items. From lending the Dali to Atlanta, to the current tour of Italian Rennaissance treasures in America, our staff are expert in assessing risks and ensuring we meet the strictest national and international standards on lending and transportation.
"With the Burrell Collection, our proposals will see us work with the trustees in advance, to agree on any items that might be included in an international tour. We have also formed a partnership with the British Museum, one of the leading authorities on loaning items, to benefit from its expertise."
l The submission was removed from the Scottish Parliament website last night at the request of the National Gallery after it had been contacted by The Herald. The Scottish Parliament said the submission had been posted in error.