When Sir William Burrell donated his collection of art and antiquities to the people of Glasgow, he laid down two strict rules:

that it should be housed more than 16 miles outside the city and that it should never be shown overseas. The first rule was rendered obsolete by the widespread control of pollution in cities; now the city council is in the throws of trying to overturn the second restriction to allow it to lend Burrell's treasures to other museums around the world.

Such a fundamental change to the terms of Sir William's gift requires a change in the law and that is currently being considered by a committee of the Scottish Parliament. With the Burrell trustees already on board, it had been assumed the direction of travel was towards approval, but now an important witness has contradicted the prevailing view.

In a written submission to the committee, Dr Nicholas Penny, director of the National Gallery in London, says the dangers of transporting art are too easily dismissed. Sir William ruled out the idea because he was worried about transport by sea (and he knew what he was talking about: he was a shipping magnate) but Dr Penny says there is tendency to think modern transport is much safer. Not so, he says: there have been several major incidents in which art works have been damaged.

Burrell's collection could never be immune from such a risk and Dr Penny's concern about it should be taken seriously. In response, Glasgow Life, which runs the Burrell, points out that in lending out 400 objects from other collections over five years, there has not been a single claim as a result of damage to any of those items, but a detailed consideration of the cases Dr Penny raises could help to make the safety measures even more robust if and when the bill is passed.

Dr Perry's other major concern centres on the projected financial benefits of allowing the Burrell to loan overseas. One of the arguments for permitting such loans has always been that it would bring in revenue for Glasgow City Council, some of which could be used to finance the repairs which the Burrell building badly needs. Dr Penny is sceptical about this argument, however, and says the financial benefits are exaggerated.

Even if this is so, it should be remembered the case for changing the terms of the Burrell bequest was never just about money. Dr Penny says loans do not lead to any big increase in visitors, but allowing Burrell's treasures to go abroad could achieve more than that. The museum's collection is as significant as those of the Guggenheim or the V&A and loaning out some of it would allow the world to see that and, in the jargon of advertisers, raise its profile. After all, the National Gallery itself makes loans with the stated aim of increasing awareness of their collection. Surely the Burrell Collection should be allowed to do the same.