The 17th and 18th century Dutch, Mr Horne says, used to encase even their living rooms in tiles, while the English stuck to fireplaces and niches. In the low-lying Netherlands, wall-to-wall tiles were probably as much a protection against damp as a design statement.
I went to view contemporary wall tiles by Ms Napp and Ms Evans. If you do the same, abandon all notion that a tile is something flat and symmetrical. The pair, university ceramics graduates in their twenties, cast colourful tiles from found objects: the double row of teeth from a bricklayer's comb chisel, a bathtap handle, the nipple-like interior cavity of a golf tee. The end-product is a wall-size jigsaw of cavorting birds, fish, found objects and abstract forms that draws the eye hither and thither.
It can come as a surprise to find that a bathtap handle embedded in a tile panel is not metal but a perfect pottery cast. Ms Evans has a "box of bits", objects beachcombed in Brighton, from which she casts - the patterned soles of plastic shoes, bones, a tin opener. The best hunting ground, she reveals, is the beach opposite Roedean School. I did not ask her to elaborate.
Besides a tiled washstand with a basin that she cast herself, the tile- collage by her friend Ms Napp that I coveted most had hooks to hang as a picture and wavy edges characteristic of her work. This composition has charmingly proportioned panels between which flit puffins, reminiscent of her childhood birdwatching in Scotland. There is a repeated symbol- like pattern of puffin beaks. The two human hands in the picture are linocuts on non-glazed porcelain, which she polishes with diamond pads to a bright, matt-white finish.
Ms Evans also imprints her clay. She uses rubber stamps. Her imprinted letter-pictures are popular as wedding presents. The trouble is, rubber stamps bounce. Her letter P bounced into oblivion shortly before she was commissioned to commemorate three weddings, one with a Pippa, the others with a Peter and a Philippa. She had to cut the leg off her R.
She also makes brightly-coloured high-relief tiles of vegetables for the Elliott James range (pounds 9), sold from the tile shop in South Woodford where Ms Napp works. They are more like sculptures than wall-tiles. A few people loathe them. I found them irresistible.
Ceramic tiles of hand-modelled, high-relief leaves serve as drawer handles in the all-tile scullery made by Kate Malone, founder of the Balls Pond Studio in Hackney, where Ms Napp was apprenticed. Cupboard doors, working surfaces, walls, shelves, are all tiled. Together with the rows of pottery jugs and mugs, the effect is colourful, gleaming, spectacular.
A German invention called Wedi board that Ms Napp uses makes fixing man- size pre-fabricated tiled panels to walls easy. It is a lightweight fibreglass and polystyrene compound containing slatted string, on which the tile- collage is assembled. Prices for the panels range from pounds 100 to pounds 1,000, depending on size. A bathroom wall was recently priced at pounds 2,500.
For comparable prices, you can buy collectable single tiles from Mr Horne, the country's leading dealer and publisher in early English tiles. A decorative 18th century British tin-glazed blue and white tile can cost as little as pounds 30-pounds 40. A blue and white tile showing a bottle kiln in Lambeth surrounded by "hovels" - the original word for pottery workers' dwellings - is priced pounds 500 in his London shop. For a typical brown-patterned medieval tile, you would need to pay a minimum pounds 300-pounds 400.
If you are after cheap space-fillers you should be able to persuade your local salvage yard to sell you Victorian fireplace tiles for a fiver each, though you are unlikely to find enough in the same style to fill a wall. Auctioneers and dealers turn their noses up at such fare unless they form part of a scheme.
Tile values in general are not fully appreciated, judging by the number that are still chucked into builders' skips. Learn to identify valuable pre-1800 hand-made tiles by their rough backs, lack of symmetry and the effects of age. And don't think of ripping antique tiles from your fireplace or niche to sell, Mr Horne advises. Left in place, they will add more value to your house than they would in the saleroom.
Jonathan Horne, 66c Kensington Church Street, London W8 4BY (0171-221 5658). Amanda Napp (0181-989 8274 or 0181-504 1152). Angela Evans (0171-613 3538).
A cautionary tale
As the price of William Morris tiles rockets in his centenary year, two researchers have made an uncomfortable discovery - some tiles said to be by Morris are not by him at all. As a result, their value has plummeted from around pounds 200 each to pounds 30-pounds 40. The evidence exposing the misattributions, a set of Victorian trade cards showing tiles stocked by Thomas Elsley a London 'art' foundryman, was purchased for pounds 5 from a secondhand camera trader in Bath antique market. Among the Elsley designs were eight in middle-eastern style that, for decades, had been wrongly attributed to Morris by authors and dealers. The buyers of the tell-tale trade cards were Richard and Hilary Myers, a midwife and a book salesman, who have just published the first comprehensive guide to Wlliam Morris tiles after more than 20 years' research. Particularly embarrassing for modern followers of Morris was the Myers' discovery that two multicoloured "Persian" floral designs, illustrated on Elsley's cards, can be seen in fireplaces at Kelmscott Manor, Morris's summer home in Oxfordshire. And at the Victoria and Albert Museum, Elsley-style tiles attributed to Morris, or his daughter May, have been quietly consigned to a storeroom. Not only did these middle-eastern style tiles have nothing to do with Morris - they were imported from Holland. Those at Kelmscott are copies of 16th century Iznik tiles. The Myers made several trips to Holland to pore over archives in tile factories and museums, noting export orders placed by Elsley and others. Conclusive proof that the tiles are not by Morris lies in the "in-glaze" high-firing process in which the pigments sink into the glaze underneath. Morris had only low-firing kilns more suitable for glass. Those Morris buffs should have known.
William Morris Tiles, by Richard and Hilary Myers, pounds 38 (inc. p&p) Richard Dennis, (01460-240044)