Buy Of The Week: Clerkenwell

his modernist duplex penthouse overlooking leafy Clerkenwell Green in London is the crowning glory of an eye-catching five-storey glass-and-stone development designed and built by the award-winning Paxton Locher partnership in the late 1990s.

It blends in well with the neighbouring four-storey buildings because its top floor is tucked back behind a 250sqm roof terrace. This elevated position, combined with dual-aspect floor-to-ceiling sliding windows, provides it with its breathtaking views across the capital - landmarks on its horizon include St Paul's Cathedral, the Old Bailey and Tate Modern.

The penthouse's current owners - a commercial architect and his partner who works in risk management - were initially attracted to Clerkenwell because of its nightlife and proximity to both the City and the West End. Ideally, they were looking for a property on which they could make their own mark, as they had very definite ideas about the type of space they wanted to live in.

They were also fans of several earlier Paxton Locher projects. So, when they heard of the firm's plans to build the Clerkenwell development, it struck them as the ideal opportunity. They then managed to negotiate a deal whereby they bought the penthouse off-plan and were allowed to take charge of the internal layout once the building was completed. All they wanted from Paxton Locher was a shell.

That was exactly what they got - a vast empty space with bare concrete floors and no dividing walls, no service connections and just a rickety old ladder linking the apartment's two floors. They drew up detailed plans and commissioned a firm of builders to carry out the work.

First, they decided to keep the upper level totally open-plan, with a view to using it as the main living space which could incorporate a kitchen, dining area and lounge. An elegant oak-and-steel staircase with glass balustrade was installed to connect the two floors, and above that a narrow central skylight running across the entire length of the upper storey.

An oak floor was laid and a compact kitchen tucked away to the back of the room with a Conran pine breakfast counter overlooking the stairwell, a fitted range of cupboards and utilities, and stainless-steel work-surfaces with a sink and waste disposal unit sunk into it.

The lower level, meanwhile, was split into three bedrooms - two at the back sharing joint access to an adjoining WC and shower room and a master one at the front occupying the entire space below the giant roof terrace. The bedrooms were plastered and painted in a neutral shade of white to match the style used in the upstairs living room.

The master bedroom was equipped with twin banks of king-sized wall-to-wall wardrobes, its own en-suite bathroom-cum-shower-room as well as two en-suite dressing rooms. Maple wood flooring was selected for the bedrooms while Portuguese limestone flagging was installed in the bathroom areas with under-floor heating and mosaic-tiled walls.

The furniture likewise was deliberately selected to accentuate the apartment's spaciousness, with just a plain dining room table and set of matching chairs occupying the back of the open-plan upper-level and a smattering of free-standing lamps, Eames swivel armchairs and a couple of comfy black leather sofas huddled around the chunky wooden coffee table in the lounge area to the front.

This section of the room is extended in summer by sliding back the windows to open the paved roof terraceproviding the perfect spot for al fresco entertaining.

The apartment comes equipped with all mod cons including air-conditioning and electronically-operated window blinds.

However, the most super-luxurious touch of all is the master-bedroom's en-suite bathroom, where a giant ergonomically-designed bronze-coloured bath is angled in front of a two-way mirrored wall panel to afford views through the bedroom and beyond to the clock on the spire of neighbouring St James' Church.

The current owners are now reluctantly moving on to pursue a new building project in Wales and have placed it on the market with Hamptons at an asking price of £1.3m.