At Sir John Soane's Museum, 13 Lincoln's Inn Fields, London WC2, until 25 September
This show is billed as 'Saving Wotton', highlighting the rescue of an almost-lost Soane house, but it is as much about the architectural manipulation of light, writes Andrew Mead.
On one wall is a large watercolour by J M Gandy of Soane's design for the Pitt Memorial at the National Debt Redemption Office and, facing it, another Gandy watercolour of the space beneath the dome in the Soane Museum itself. For both of these were precedents for Soane's Wotton House showpiece - its subtly dramatic, top-lit entrance hall or tribune, rising the full height of the house.
Wotton House at Wotton Underwood in Buckinghamshire was built between 1704 and 1714 (its architect is unknown), and Soane became involved because of a catastrophic fire there in 1820; the urgent scribbled summons to him from the owner, Lord Buckingham, appears in the exhibition. But the house, Soane's contributions included, had to be saved a second time, for in 1957 it was due for demolition until Elaine Brunner - actress, Soane enthusiast and clearly a formidable personality - bought it and asked Donald Insall to restore it.
Along with Giles Worsley, Peter Inskip and the show's curator, William Palin, Insall is a contributor to the catalogue - scholarly, attractive and inexpensive (£12.95), as the Soane's catalogues usually are. He does not go into great technical detail about the restoration - this isn't a show on the mechanics of 'saving Wotton' - but gives a general outline and flavour of the whole experience, including drives with Brunner in her husband's Jaguar, when 'she rarely advanced beyond third gear, but it was all part of the excitement'. Following her death in 1998, the house passed to her daughter and son-in-law, April and David Gladstone, who are continuing the restoration.
Continuing, because there is still work to be done in the grounds - 'reinstating the connection between landscape and architecture is at the heart of Wotton's recovery, ' says Kate Graham in the catalogue - but also because the tribune is still obscured by floors inserted by architect A S G Butler in late-1920s alterations to the house.
This shouldn't detract from what's been achieved at Wotton already, or slight the significance of Soane's other interventions there - especially the long north-south corridor with its serial arched openings. But the studies for the tribune that feature in the exhibition, flanked by those two large Gandy watercolours, show Soane's perseverance and dexterity in resolving the problems of the design, and suggest how stunning it must have been when built.
As there are no photographs or drawings of this hall before the alterations, and little in Soane's archives of the final scheme, the most vivid representation of it is a watercolour perspective by Ptolemy Dean, notionally reconstructing this lost space, with its complex interplay of direct and diffused light. Saying that they face 'a big challenge, both financially and architecturally', the Gladstones hope to make this reconstruction a reality, and one can only wish them well.