The money markets may be wobbling but developers report a boom in building bespoke properties. They provide the site and the builder and they work with the purchaser on the design. Buyers get the house they want, whether a grand mansion or modest box, while developers get a guaranteed buyer at the end of the build process.

Often clients want to stay in their current location and ask the developer for a new home to be built on their existing plot.

Among developers offering this service is Heronslea, which can take you from choosing a location to giving you the key to a furnished home. It has 20 years of land acquisition behind it and good links to local authorities in North London and South Hertfordshire.

Fusion Residential has a bespoke building/project-management arm called Your Fusion. Its projects in North London and the northern home counties range from 5,000 sq ft to 10,500 sq ft and usually sell for seven-figure sums. Luxuries added by Fusion have included a five-a-side football pitch and a bespoke cinema.

Among sites on the market, Rescorp Residential is offering a family home on Acacia Road in St John's Wood, with permission to more than double its size from 3,660 sq ft to 7,619 sq ft.

As it stands, the property is laid out over four floors, with the proposed floor plans envisioning a two-level basement as well as a single-storey side extension with lift to all floors. Plans for the sub-basement include a 1,700-sq ft spa, health and fitness suite.

Do not, however, expect to construct a neo-gothic castle here. The site is in the St John's Wood Conservation area, guarded by a planning committee so fierce it could work night shifts at the gates of Hades or, as Rescorp director Vic Chhabria puts it: "a faithful planning committee fully dedicated to preserving the architectural and historic character buildings of the vicinity".

Consent is required from Westminster Council for demolition of most existing structures, removal of trees and front boundary walls, gates or railings above one metre.

The permission in place enables the new owner to open up the exterior wall, creating a generously proportioned frontage, driveway and south-facing garden.

Mr Chhabria adds: "We estimate that it will cost £3 million to undertake this exciting project, which will enable whoever buys the property to put their own personal stamp on the interior design and the specification.

"By obtaining planning permission, the owner of the home has increased its value and desirability by approximately £1.5 million."