“Exceptionally, they also have their own gardens of about 70ft.” A double-fronted corner house (albeit with a roof terrace instead of a garden)on Paultons Square is currently on the market for £2.8m. Smaller houses are around £2.2m.Chelsea Square is one of the few places with houses that lead directly into a garden, but in Notting Hill, west London, it is a feature of some of the loveliest garden squares, where the rear of many houses back onto communal gardens. In the film Notting Hill, the last we see of Julia Roberts is in Elgin Gardens, a square of four- and five-storey houses that rarely change hands. Rob Atkins from the estate agents Foxtons says families tend to stay put there for years.”It is very safe for children and all the squares have a strong community feel Take Ladbroke Square. You can go straight from your house into six acres of garden with a tennis court.” A basement and sub-basement with its own garden leading into Ladbroke Gardens is being sold for £1.2m through Foxtons, who are also marketing a house in Elgin Crescent for £3.5m.At these prices, the use of a private garden might fairly be regarded as a reasonable expectation. Yet although London has an exceptional number of houses with only communal gardens ­ 70 took part in English Heritage’s recent Garden Square Day ­ agents have waiting lists for the most popular.And they may not be out of most people’s financial reach.

Deborah Battsek was renting a flat in Montagu Square, close to Marble Arch, when her first child was born. The number of police signs in large public places warning of pickpockets, muggers or worse made it hard to completely relax, and so the gardens proved a haven. “Much as I love Hyde Park, when the sun comes out, so do people in their thousands. The hardest thing to find is peace and quiet,” she says.”I don’t think I had ever put a foot in the garden before my son was born, so it was a wonderful discovery. Hardly anyone used it, so I could take him into the garden and let him play on a rug while I got on with my work. If he fell asleep I didn’t have to struggle home up four flights of stairs.

Plus, as you do feel vulnerable as a new mother, it was so relaxing to know that the gardens were safe.”Another factor that persuades people to consider a home without any private outside space is the pressure of a heavy work schedule. Foreign buyers who spend only a few months a year in London have long seen the advantage of enjoying a garden without upkeep, but the benefits are also increasingly appreciated by those who would normally shun the idea.Jane Ewing, whose job takes her abroad frequently, found that keeping up her garden became a chore rather than a pleasure. “When I first moved to London I rented a flat in the Bloomsbury area and loved the fact that it was leafy as well as central, but I was dying to get stuck in in my own garden.”I bought a small house in south-west London and devoted nearly all my free time to planting and weeding. The garden looked spectacular for a month in the early summer, but after a few weeks away I would come back to a brown, frizzled-up sight and felt like weeping. Now, even though I only have use of a garden, I have long chats with the gardener, so I feel involved.”When it comes to prices, the garden-square factor is felt farther afield than the prime areas of central London.

In Kennington, south-east London, there is a 20 per cent premium on houses in St Mary’s Garden and West Square, both with private communal gardens ­ and even on Cleaver Square, which is open to the public. Nestling between two huge traffic junctions, it had a facelift two years ago with help from lottery funds. A block of tarmac has been transformed into a Parisian-style of garden, with gravel, benches and a space for boule. Children can even be kept under surveillance from a nearby pub.According to Adam Shea of Winkworth, a £630,000 house the estate agency isselling in Cleaver Square would be closer to £420,000 a few streets away. Addington Square, off the Walworth Road, is another little-known oasis, he says.