The true case for abandoning admissions charges for the national museums is not socialist, it is patriotic. Let Mark Fisher, Labour's junior National Heritage Minister, carry out his review. But when he decides, as he must, that entry to the Science Museum and the Victoria and Albert should be free, let's not hear too much about doing it for the sake of people on low incomes. That is a consideration, but a small one. The case for open admission rests on a Victorian value Lady Thatcher and the Tories never had much time for: institutions created in the public interest and for the celebration of public culture must be open and inclusive.

There is a distinction, subtle but vital, to be made between nationalism and patriotism. One is atavistic, inward- looking, foreigner-hating; the other is relaxed, open to the world, keen to share what is best in a country. A British patriot can, for example, be the most enthusiastic advocate of membership of the European Union. Someone genuinely fond of this country might take pride in that great institution in Bloomsbury, the British Museum, because it is open to all in principle and in practice. To all those concerned about the provenance of its sculptures and artefacts, the reply is: the past is past and you, whether Greek or Roman, come here and browse, free, gratis and for nothing. That visitors have to pay to enter the Louvre or the Kunsthistorische Museum or Trajan's Market or the Acropolis is utterly irrelevant - as is the fact that most of the Smithsonian Institution is free. The argument against charging simply says: in Britain we are proud of that great collector's and conservator's instinct which brought together these great collections and even prouder of the fact they are free.

Except some of them are not. The National Gallery and the Tate hold out, but at the National Galleries and Museums on Merseyside there is a muttering. Even the trustees of the British Museum are once again wondering about charging visitors. Our national museums dedicated to fine arts, the Navy, war, natural history and science all charge. For all their imagination in family ticketing and provision (for example at the Victoria and Albert), at certain times sampling the national collections can be a costly business. There is an argument that says financial stringency has improved the management of all the national collections; indeed, that it has pushed curators into imaginative collaborations with the private sector. There is nothing wrong with hiring out the dinosaurs as a party backdrop - provided vital curatorial and educational functions are not downgraded by a dash for cash. Trustees should not suddenly stop seeking outside funds. But charging is not a necessary condition for any of these managerial benefits. Besides, the argument of principle against charging is compelling.

Mark Fisher needs to spend little time on that. His question is how, in these Brownist financial circumstances, he can find the money to allow trustees to tear up their tariffs.

The National Lottery has made that question far less difficult. No, the funds available from the nation's gambling are finite and yes, the Labour government has already made free with them, rhetorically speaking. Proceeds from the same bet cannot simultaneously buy chalk and medicine, and then pay for overtime for the guards at the Imperial War Museum. But the National Lottery already contributes considerable sums to the national collections, in the form of capital grants. Even though, in some cases, these grants are matched by private sector money, there is room in the financing formula for substituting revenue grants (which would allow the abandonment of entrance charges) for capital awards. The museums' grants in aid from the Department of National Heritage are being squeezed in the Tory spending plans inherited and endorsed by Gordon Brown. But is the Department's aggregate budget so slim that the Government has no room for manoeuvre?

More difficult than money is the question of whether support for the national collections would put additional pressure on other museums - such as those rewarded yesterday by Chris Smith with the accolade "pre- eminent", including the National Motor Museum at Beaulieu or the Rural History Centre at Reading. Of course the national collections are not all in London. The Science Museum group includes the National Railway Museum in York and the National Museum of Photography, Film and Television in Bradford. The official list of national collections includes the Walker Art Gallery in Liverpool. Any comprehensive list of (British) national collections would need to include the National Gallery of Scotland. Britain's museum culture is blooming and booming. New installations open all the time. Not all are successful - the Royal Armouries, a national collection now based in Leeds, has been struggling. But to try to paint all museums as cash-strapped and desperate is completely false - look at the Fitzwilliam Museum in Cambridge (which does not charge), fighting against its donnish neighbours over its modest and tasteful expansion plans.

Giving extra support to the national collections in order to allow them to head off a decision to impose charges will be construed by some as elitist. It is nothing of the kind. Just as there is a hierarchy of universities based on the quality of their research which necessitates different levels of support, so the national collections have to be recognised as that - national institutions that command our loyalty and appreciation and, belonging to us all, have no place for turnstiles and ticket machines in their entrance halls.