The initial impetus came from the need to improve roads and pedestrian routes under the viaducts, which were often dank and even threatening. All 97 of these routes have been improved with better lighting, CCTV, colourful cladding and artworks. Now attention is turning to the nearby arches.

Arches under Vauxhall Station have become a “Little Portugal”, with a café, restaurant and shop as well as an Italian delicatessen. Tas, a Turkish restaurant, is housed in arches on the approach to Waterloo East Station. The big question in arch conversions is whether to expose the internal brickwork. Tas has gone for a clever middle way, introducing suspended wooden arches for an intimate feel and incorporating uplighters which create soft light.

The most dramatic conversion is Wagamama under the arches next to Cannon Street Bridge, Vinopolis and the lively stalls of Borough Market. Here the arches are lofty and broad with an almost Roman monumentality. Wagamama’s minimalist ethic was set ten years ago by architect John Pawson. Now design work has been taken over by Jonathan Pennington. He explains: “We could have drylined the arch, keeping the space but losing the brickwork. Instead we cleaned the brickwork with water and brushes and a little light sandblasting — too much of this and you risk taking the surface off the stock brick and creating a lot more leaks.”

Now that the arches around Borough Market have filled up, the next big opportunity lies to the east of London Bridge Station — in Crucifix Street stand a series of the most handsome railway arches in London. There is rich polychrome brickwork and arches with a black and white “Liquorice Allsorts” treatment. The pioneer is the Iranian fashion designer Pierre Garroudi, who has established himself in one of the arches with a clothes shop cum gallery.

The arches beneath London Bridge are almost as deep as the Bishopsgate arches north of Brick Lane, which were savagely cleared by London Transport. When the Spike, London’s tallest building by Renzo Piano, is built beside the station, the arches will fill rapidly with sports clubs and restaurants.

An alternative solution is to convert the arches into studio office space. This has been done with a group of 15 arches in Wootton Street east of Waterloo Station. Steven Cooper of architects Lewis Hickey says: “We have waterproofed, soundproofed and insulated the arches and introduced mezzanines. They have let very well to design and marketing businesses.”

Behind the arches programme is Savas Sivetidis, the director of the Cross River Partnership, which has helped to direct more than £200 million into projects such as the new Millennium and Hungerford bridges. The next challenge is whether walks can be opened up along the viaducts, making new routes such as the Jubilee Walkway along the South Bank.

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