“The thing is, I’m hardly ever there,” he says of his London home, Clerkenwell House in London EC1. “So it just doesn’t make sense to keep it.”

We’re squeezing a conversation between his many appointments as a garden designer that take him all over this country and the world, so it is hard to see how much benefit he gets from owning the unique three-bedroom townhouse he bought in 2002 for £875,000.

At the time, he was searching for a London base. “When I first looked at the details I wasn’t sure, but as soon as I walked in I thought, ‘Wow, this is amazing!’” says Maynard.

From street level, the facade gives the impression of an upmarket office block. Frosted glass obscures the view from outside, and a row of silver birch trees in a tall galvanised container is the exterior’s only embellishment.

The basement, lit through pavement skylights, contains a bedroom and bathroom. The ground floor is devoted to the entrance hall and utility room. On the first floor is the second bedroom and bathroom, the main bedroom suite is on the next floor up and above that is the kitchen. Keep climbing for the living room, and, at the very top, a small office and the only outdoor space the property has, a decked terrace.

The house was the brainchild of the architect Jo Hagan, who used to pass the then-derelict site every day. It measures just 11ft wide by 28ft deep, so Hagan built upwards to provide 1,969sq ft of living space over seven floors.

He put in a small lift — it fits two people but they need to know each other well — and there is a narrow staircase.

On paper, the house seems as though it would be hard to live in, racing up and down between floors when you want to use the bathroom or make a cup of tea. “But,” says Maynard, “you only really move between two floors at a time, and anyway most town houses have no more than two rooms on a floor, so there are still lots of stairs.”

He only spends a couple of nights a week running up and down the stairs of the house on Golden Lane or out and about in the capital. The house is handy for Tate Modern, Spitalfields and the Barbican with Old Street Tube station just down the road. Usually, Maynard lives at Guanock House in Lincolnshire, with five acres of garden that he has designed himself.

Clerkenwell House is “completely different to anything else I have ever lived in. It feels like a New York apartment,” says Maynard, “and you also feel connected to the outside because of all the glass. You don’t feel at all exposed, because the lower floors and bedrooms have frosting and in the kitchen and living room you are so high up people can’t see in.”

He claims that all the furniture was “easy to get in”, although closer questioning reveals that it actually required a crane and an extendable ladder, as it had to go through the windows on the floor on which it was to be placed.

There is no scope for moving furniture around the house after it is in, and it could prove awkward if you fancied a change of style. “You couldn’t fit a chesterfield in,” says Maynard.

But if a chesterfield is your style reference, Clerkenwell House probably isn’t for you. Maynard has painted it throughout in neutral shades which show off his collection of work by Paul Ryan, winner of a Jerwood Prize for drawing in 2001. The pièce de résistance is the reading room at the top of the house — a small nook with a ponyskin day bed beneath a conservatory roof — and on the same floor the decked roof terrace with more birch trees in galvanised containers.

Throughout the house, there are architectural details that remind you why the house won a clutch of awards and has a £1.15m price tag.

In the second bedroom, the wet room has a sunken shower/bath, while in the kitchen a 40cm-wide cupboard door hides the modern equivalent of a priest-hole — a huge storage space for all the items that would otherwise clutter the minimalistic interiors. The house also has a built-in vacuuming system.

It’s not a home for a young family — you would need lots of stair gates and nerves of steel to allow a toddler to run around — but agent Russell Chopp of Space Station is convinced the right person is out there. “You are paying for the uniqueness of the house,” he says. “There’s nothing else like it.”

Jo Hagan, 020 8986 8111, www.usearchitects.com; Space Station, 020 7613 6262, www.thespacestation.co.uk

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