The Royal Collection has bought 11 views of rooms with charred beams, collapsed floors and ceilings open to the skies; Creswell has an extraordinary affinity for architecture and catches the feel of the 'Gothick' rubble with impressionistic washes.
The paintings, along with 85 other watercolours by the 37-year-old artist, are on sale and can be viewed at Spink's in King Street, St James's, central London.
The 85 watercolours are priced from pounds 700 to pounds 4,000 and are likely to be snapped up fast - contemporary realist watercolours are a very strong market at the moment, especially if the subjects carry a hint of nostalgia as Creswell's do.
He attracted royal attention by his book The Silent Houses of Britain, published in 1991. He had travelled round abandoned stately homes, evocatively painting the decomposition of both interiors and exteriors. He loves to catch sunlight slanting through windows or making intricate patterns of light and shade out of doors.
The new works include some notable views of Russian buildings around St Petersburg in the snow - and evocative interiors of the Hermitage. There are also some sun-drenched corners of old Tuscan gardens that he made near Viterbo while teaching a summer course for the Prince of Wales's Architectural Trust.
Another watercolourist who makes the most of his summer holidays is Nigel Ashcroft, 43, who has an exhibition at Frost and Reed (16 Old Bond Street, W1). His summers are mostly spent in the Dordogne where he paints small corners of old buildings with intensely detailed accuracy, usually in strong sunlight.
He has a wonderful eye for textures - stone, faded paintwork, old advertisements, geraniums - and their lacy shadows on walls; even an old tin bath and a haycart are rendered with painstaking accuracy.
He lives in Gloucestershire and has a particular penchant for painting the accoutrements of a cricketer. His bat, his ball, his straw hat and his white pullover are draped over a bench in the garden waiting for use, or perched on a chair dappled with sunshine - though he never paints the cricketer himself. Armstrong's watercolours are strictly uninhabited.
Four of his paintings had sold while the gallery was in the process of hanging his exhibition last week - including the most expensive, a cricketing still-life at pounds 1,700. Tony Neville, gallery director, said confidently: 'We'll sell the lot. We always do.' This is Armstrong's fourth show with Frost and Reed.
More and more Mayfair galleries are beginning to sell contemporary watercolours, because they are so easy to shift.
Christopher Wood, the Bond Street specialist in Victorian pictures, opened a new business called Christopher Wood Contemporary Art last autumn and is preparing a show of watercolours by John Stickland Goodall entitled 'Edwardian Memories'. It opens on 19 April. The artist is 85 and paints happy scenes of his childhood priced between pounds 1,800 and pounds 3,000.
Mr Wood's February show was devoted to an 80-year-old landscapist, Robin Bagot, whose watercolours echo Cox and Cozens; they were priced from pounds 200 to pounds 850 and 76 were sold in two weeks.