Inside Ian Simpson’s Manchester Penthouse and the SimpsonHaugh Studio

A mad idea, he admits, at level 47. There are no bugs and no birds up here, so there's no ecosystem either. The trees can't set fruit without pollination. They have been very happy all the same.

Simpson calls living at height a sanctuary. The busy life of the city is 45 seconds away, and the slight sound of it comes through the glass and keeps you engaged with it. In the mornings the light comes in from the north, in the afternoon it fills the garden, and in the evening it reaches the drawing room.

He wanted as few walls and doors as possible, so only the bedrooms and bathrooms are enclosed. Everything else is one flowing sequence of spaces. The kitchen lives behind screens and doors that retract, so the ovens, the microwave and the storage can be popped away and it sits comfortably among the paintings and the sculpture.

The snug is the room that can be made small. Curtains drawn across in winter, opened up to the view and the light in summer. Teak furniture, reds and oranges in the paintings, the TV, the family. Upstairs is the studio he designed for working from home before working from home was popular, a bridge across the garden at canopy level where the day starts with writing or sketching.

Simpson is not a minimalist and has been collecting most of his life. Mid-century glass from Italy and Scandinavia, the Italians exuberant, the Scandinavians restrained and clear. A 1952 lancet piece by Timo Sarpaneva was an inspiration for the asymmetrical form of One Blackfriars in London. A one-off Scandinavian cabinet, its veneers laid over one another, became the wall of the Queen Elisabeth Hall in Antwerp, a run of timber panels with scooped forms cut into them.

The oval carpet under the dining table was woven from his first sketch for Urbis, completed in 2002 and now the National Football Museum. At the top of the stairs is a layered timber sculpture he bought 45 years ago, said to have come from a casino in Milan. He kept it under the bed in a small London flat until this apartment gave it somewhere to go.

The walk to the office takes ten or fifteen minutes and it was raining. It goes past Deansgate Square, the first of the New Jackson developments, 1,500 apartments on land that was slum housing and disused warehousing six years ago. Then Contour, two towers whose corners open up and close down along their height, an undulating edge that also improves the apartment plans inside, with a new public green space going in between them. Then Albert Square and the town hall, one of his favourite buildings in Manchester, under a very expensive restoration and soon to be a town hall again.

Simpson and Rachel Haugh set up the practice almost 40 years ago. She had only just left college. He was older, had worked at Foster and Partners in London, and taught the undergraduate years at Manchester University School of Architecture. They had no work whatsoever. The first jobs were house extensions passed on by lecturers, and every hour went on competitions, all of it hand drawn on drawing boards.

Then they won an Architecture Foundation competition for the Foyer, the only shortlisted practice outside London or the Continent, and spent the prize money on Macintosh computers. That was 1992 and their first introduction to CAD. In late 1996 they won the competition to masterplan the city centre after the bomb, and out of it came Urbis, No.1 Deansgate and the tower he now lives in.

The senior team has stayed. Some have been with the practice 30 years, and most of them were his students at Manchester University. Below them, more than half the office is under 35, with new Part 1s and Part 2s arriving every year. Finding people who share the vision and the ambition and are culturally on the same wavelength is, he says, critical.

“Bespoke are very good at managing that process and bringing together the right sort of team, and that's something that we really value at the practice.”

Simpson was born eight miles from the tower, in Bury, one of the eldest of six. His father was a demolition contractor who took down mill chimneys with gelignite, and Simpson spent his youth 200 feet up them with a sledgehammer. When the bomb went off in 1996 there were 400 people living in the city centre. There are now about 100,000, and he wants twice that to match the density of London, Paris and Barcelona. People are where ideas spark.

The next 30 years, as he sees them: twice the population in the core, investment spreading to the ten boroughs, an underground station, the rail links north.