Fifteen years ago, a new television channel, BBC4, was launched in the United Kingdom with a remit for broadcasting on intellectually challenging subjects. From the beginning, the visual arts were prominent and after a rather wobbly start – a film on Goya by Robert Hughes is said to have had only 15,000 viewers – the channel’s numerous documentaries on art-historical subjects have often won both popular and critical esteem. Few, however, have sought to break the pattern so definitively established by Civilisation nearly half a century ago. Although Waldemar Januszczak, Andrew Graham-Dixon or Alastair Sooke may not sound much like Lord Clark, they are essentially doing the same thing: giving lectures. Among the few exceptions is Britain’s Lost Masterpieces, conceived and presented by Bendor Grosvenor.1 It was first broadcast in 2016, and its second series concluded last month. Although modest in scale – there have been just seven episodes in all – it is doing something unusual for television: showing how art historians work.

The concept for the programme emerged out of the Public Catalogue Foundation, the charity founded by Fred Hohler to publish all the oil paintings in British public collections. When in 2016 its database was put online as Art UK, Grosvenor realised that its high-resolution images presented an enticing challenge: of these 212,000 paintings, some 40,000 are unattributed. The programme has a simple formula. Grosvenor follows his eye to a promising looking work, researches its history and in most instances has it cleaned and conserved by Simon Gillespie before seeking the verdict of an expert. Each episode has turned up neglected paintings of remarkable interest, including a possible Raphael Madonna and Child at the National Trust for Scotland’s Haddo House, Aberdeenshire, and an indubitable Rubens portrait of George Villiers, Duke of Buckingham, in Pollok House, Glasgow.

By focusing only on works in public collections Britain’s Lost Masterpieces avoids the slightly wearisome stress on financial value in most popular programmes on similar subjects, such as BBC1’s Fake or Fortune? Admirably, it suggests the richness of Britain’s regional collections – the programmes have ranged from Swansea and Belfast to Derby – and also the challenges they face. Few galleries outside London have the curatorial resources to undertake research of this sort, a point that the programmes do not labour, although issues of funding are gently hinted at in a quick shot of crumbling masonry at Carmarthenshire County Museum, where Grosvenor tracked down unidentified portraits by Mary Beale and (possibly) by Peter Lely.

The programmes also manage to convey a considerable amount of art-historical information, either in asides by Grosvenor explaining, for example, what a pentiment or a capriccio are, or in research trips – in one, he examines a Van Dyck grisaille at Boughton House that provides a model for the pose of the Lely portrait. The fundamental if usually laborious issue of provenance research becomes an engaging quest for clues and Grosvenor’s joint presenters ( Jacky Klein in the first season, Emma Dabiri in the second) explore the wider background of the artist, subject or earlier owner of the painting. But a deeper value of the programmes lies in their honest approach to an issue that most museums and galleries shy away from discussing in public – condition.

Most of the paintings that Grosvenor tracks down have been neglected because they are dirty, damaged or overpainted, and usually all three. The cleaning and conservation they undergo is often revelatory. Particularly memorable in the second series was a heavily over-painted work in Derby Museum of a bridge. The fact that another painting in the collection, a view of the Colosseum by moonlight, had in 2015 emerged from under crude twentieth-century overpaint to be recognised as a work by Joseph Wright must have been grounds for optimism. The painting of the bridge did indeed turn out to be a view by Wright of the Ponte Nomentano near Rome, yet despite this startling transformation the programme emphasised the limitations of what conservation can achieve in making damaged works of art aesthetically acceptable. When the painting was shown to Brian Allen his first comment – before confirming that it was by Wright – was ‘this picture has had a hard life’. Similarly, Grosvenor pointed out that the Rubens portrait of the Duke of Buckingham had suffered minor but irreparable damage caused by the separation at some stage in its history of the pieces of wood on which it was painted.

The frankness with which the programme dealt with these matters raises the question of why museums and galleries tend to avoid drawing the public’s attention to them. There seems to be a consensus that issues of condition, and the work of conservators, are too complex to be explained to gallery visitors as a matter of course. When attention has been drawn to the condition of works of art it has tended to be in the context of exhibitions, where detailed information can be provided – the National Gallery’s Close Examination: Fakes, Mistakes & Discoveries in 2010 was a good example. Other instances are paintings that have been so heavily restored that it would be seriously misleading not to explain to the public what has happened, as in the Fitzwilliam Museum’s unveiling last year of Sebastiano del Piombo’s Adoration of the Shepherds, heroically rescued by the Hamilton Kerr Institute from the disastrous effects of its transfer to canvas in the eighteenth century.

As our current ‘Art of Conservation’ series demonstrates, art historians have long grasped that issues of condition underpin our understanding of the art of the past, but Britain’s Lost Masterpieces might encourage them to share this knowledge with a wider public. In any case, the series has demonstrated that art history in the empirical tradition exemplified by the Burlington Magazine – a combination of connoisseurship, documentary research and scientific analysis – can, if treated in an open and engaging manner, captivate an impressively large audience.

1 The programme is broadcast outside the UK as The Art Detectives.