The demand for lateral apartments — ones that stretch the full width of a building, or sometimes across two buildings — is growing fast because, while they may have the same square footage as a house, they can offer much more true living space.
In a city short of space, one-level living can do away with staircases, landings and awkward corridors to provide larger rooms and space that is ideal for entertaining. And for high earners, they offer great wall space for displaying large-scale art.
With rooms being longer and wider, lateral apartments tend to have high ceilings, so dimensions stay in proportion and that creates a sense of extra space. So, too, does having outside walls and windows further away from the centre of the home. For families, there's no shouting up the stairs — and there's much less chance of children shutting themselves away to get up to mischief.
A downside in central London is that such flats can prove expensive — twice the £1,600 a square foot paid for conventional homes. However, according to agents Knight Frank, more than 90 per cent of new central London apartments are laterals. To satisfy demand, houses are being converted into lateral flats by inventive developers.
In Mayfair developer Oliver Burns has converted two neighbouring Grade II-listed Georgian houses into three lateral apartments, a duplex penthouse and a triplex, which all straddle the breadth of both buildings. Prices for the two remaining flats at The Walpole start from a pretty eye-watering £11.5 million for a 3,020sq ft home.
Laterals are more affordable in Fulham and Brook Green, says Rupert des Forges, head of apartments at Knight Frank. "Whole houses are being combined, with entire partitioning walls being knocked down to make properties that create very large lateral spaces on each floor," he explains.
In east London, warehouses are ideal for conversion to magnificent lateral apartments. In the Tapestry Building, near Liverpool Street station, there are two laterals remaining for sale through Savills, from £2.4 million.
In the home counties, laterals on the market in Esher, Surrey, include a 2,186sq ft home at Milbourne House, Princess Square, on offer for £2 million through Knight Frank. Like many other laterals, the apartment's communal parts are open-plan, so the adjacent dining and living areas have a combined width of 42 feet.
Ed Tryon, director at London buyers agency Lichfields, says three quarters of his clients want lateral apartments, knocking conventional houses off the top of the popular table during the past three years.
Tryon says laterals have become more popular since 2009 because international buyers are now more numerous in the market. They are better-used to apartment living than many wealthy British buyers, and prefer the living space a lateral flat can offer. In the first six months of this year, three quarters of central London's new-build homes and half of its resale properties were sold to overseas buyers, reports Savills.
Ed Tryon adds that overseas buyers with experience of living in cities such as New York or Singapore are no strangers to apartment living, which is often seen as more secure and easier to lock up and leave.
Unlike a house, laterals don't have a front door opening on to a street. Overseas buyers, especially those who expect to live in London for only part of the year, value the management services that apartment blocks provide.
Modern blocks containing lateral apartments, like the costly and much-publicised One Hyde Park in Knightsbridge, also have communal facilities, including spas and gyms.
However, British buyers are beginning to warm to lateral apartments and often knock two flats into one when the chance arises. In January, a British buyer purchased two apartments at Riverside One, the Lord Foster designed building in Battersea, combining a modest one-bedroom flat with 1,000sq ft of space with a larger 3,200sq ft neighbouring apartment to create a supersize, 4,200sq ft lateral home, says Tryon.
Creating lateral apartments across existing buildings may be complex but can add value, says Knight Frank's Des Forges. "Planning is not as much of an obstacle as negotiating the listed building and landlord consents involved," he says. Overseas buyers might have led the demand for laterals, but UK buyers are quickly catching the bug.