Thomas Sutcliffe: Slavery isn't just a 'black' subject

In common with a number of other public institutions, the Victoria and Albert Museum in London is currently doing its bit to commemorate the parliamentary abolition of the transatlantic slave trade 200 years ago. But if you're planning a visit to Uncomfortable Truths, you'd be well advised to wear a good pair of walking shoes and brush up on your map-reading. Because, although Uncomfortable Truths is described as an "exhibition", the word's implicit promise of a sequence of objects that are not for sale, terminated by a collection of objects that are, is not fulfilled here.

What Uncomfortable Truths consists of is a series of "interventions" - specially commissioned works that have been placed throughout the galleries and which are further accompanied by five gallery trails - linking together objects in the permanent displays that have a hidden connection to the history of slavery. Given the vanishing improbability of visitors just stumbling across the exhibits, two maps have been produced and, shuffling between the two, you embark on the often frustrating task of tracking the exhibition down.

It is a fugitive affair. This is partly because of the nature of the "interventions" themselves, which are intended to be embedded in the general collections rather than segregated into a separate space. Lubaina Himid's contribution, Naming the Money, for instance, consists of life-sized cut-out paintings of slave servants, sometimes propped up behind the barrier ropes of a display, sometimes tucked into a corner of the gallery so that only the truly vigilant will notice them.

It doesn't exactly help that the scale of the V&A's maps mean that you only get a rough guide as to where individual exhibits are - or that the exhibition and the trails overlap each other, so that you find yourself flickering between the two indecisively. Take two flights of stairs now to knock off item seven? Or wait till later when trail four will bring it within striking distance?

The exhibits themselves are variably interesting, as you might expect from any similar exercise, but the overall experience prompts several thoughts. The first is an uncomfortable one - but may be a different kind of discomfort from that which the V&A had in mind.

It is that these objects have an essentially servile relationship to the institution in which you find them. The service they perform is to make it clear that the V&A is meeting its multicultural obligations - and it's a service that they perform with great discretion. They don't get in the way, they don't speak unless spoken to, indeed, you might hardly know they were there if they weren't pointed out to you. When you find one installation - by the video artist Michael Paul Britto - tucked into an alcove on a stairwell, you find yourself resisting the word "marginalised", but resisting it without a great deal of success.

And that leads to a second uncomfortable thought, which may well be to the credit of the exhibition rather than one of its failings. That is that Africa is to this day an unmentioned absence in the Victoria and Albert - an empty space in its map of the world cultures that are worthy of admiration and emulation.

The founding instinct of the museum was to offer the manufacturers of Britain a repository of exemplary objects that would inspire improvements in craft and design. But although you will find galleries devoted to Islamic art and Indian art, to Korean art and the art of Japan, it is very hard to find any objects from sub-Saharan Africa. And this is, in part, the legacy of Victorian racism.

The culture of Africa was certainly of interest to the builders of empire, but it was so as the raw material for ethnography, not aesthetics. Since the presumption was that African art was "primitive", a kind of living pre-history of European civilisation, how could it be expected to propel that civilisation forwards? And that casual assumption surely had a direct connection to the assumptions that had sustained slavery.

Acts of redress aren't always easy to get right, though. Uncomfortable Truths obviously sets out in that direction - and I wouldn't want to question its motives - or even the quality of some of its exhibits. But even the fact that all of those taking part are of African or Caribbean origins sends a slightly unwelcome message. It's as if the history of slavery is in some way regarded as a "black" subject, when the truth is that it's very much a white subject too - or should be. It sits there, just beneath the ground, betrayed only by dips in the surface and odd bare patches in the grass - and its archaeology can't properly be revealed by piecemeal interventions. Uncomfortable Truths shouldn't have been dispersed through the corridors, to lurk in corners or go unregarded on the landings. It should have been a blockbuster.