A ruined medieval castle is brought back to life by an extraordinary modern dwelling

Surrounded by medieval field systems, woods and fishponds, the once-fortified manor house is approached by a small bridge over the remains of the moat. Soft pink sand stone walls glow on even the dullest days. The two front halls screened by the east elevation, dating from the seventeenth century, are now courts open to the sky. But there is a long table where you can sit outside in the evening, with logs flaming in the fireplace and long shadows falling on the brickwork floor between the stone mullions and through tracery.

The three oldest walls of the central core - in some parts nearly two metres thick – have been tied with massive concrete beams, which span the voids left by the catastrophic fire. New brickwork is knitted into medieval masonry, stabilising the walls and creating a recessed enclosure. After lengthy consideration, Danish brick was used on account of its subtle colours, blending into the sandstone yet allowing the new work to be clearly identified. Though wholly irregular, junctions between past and present are precisely defined. Stepped brickwork detailing emphasises the verticals in Tudor style, as do the frames of the large new windows. We have taken our cues from the dignified elegance and rich rhythms of the Gothic mullions,' says William Mann.

The main contractor was William Anelay, who applied traditional masonry and carpentry skills to materials selected to provide the most environmentally friendly solutions. A new feature is the central staircase, which went through three or four designs before being constructed of kiln-dried oak, with a twisting bronzed-steel baluster forged by the Devon blacksmith James Kendrew. It leads to the first-floor kitchen, dining and sitting area - a glorious space floored in bleached oak, animated by light falling on the variegated stone and by views of the historic landscape that puncture the modern, seventeenth-, fifteenth-, and twelfth-century walls.

The kitchen, built in the Landmark Trust's workshop to Witherford Watson Mann's design, again combines old and new, with fumed-oak units and Brazilian slate surfaces. Rich purple-brown Spanish terracotta tiles lining the back-wall niche are also used for the kitchen, bathroom and hall floors. Red Puginesque chairs add a theatrical note to the dining space, sourced by John Evetts of the Landmark Trust, who was responsible for furnishing Astley. The large walnut and gilt ottoman, cut down from an Italian lit bateau, is perfectly positioned for contemplating the fourteenth-century collegiate church of St Mary. A pair of late-nineteenth-century Dutch bronze chandeliers provide additional downlighting. A local resident offered the Trust three Victorian paintings of Astley, which now hang in the ground-floor passage way. On this level, four bedrooms and two bathrooms have been created, with stained birch panelling and french windows opening out on to brick and stone terraces and the gar den beyond. No detail has been overlooked, from the bronze door furniture by Izé to the lift for disabled access, cleverly inserted in what was left of a collapsed light shaft.