Inside St Pancras Chambers

St Pancras station, London. From next year, the first two floors of George Gilbert Scott's salmon-pink building will form a 244-room, five-star hotel called Renaissance St Pancras. Above this sit 67 now-completed flats
Photograph: Andrew Holt/Getty Images

The magnificent building began life in 1873 as the Midland Grand Hotel. The hotel, by then very old-fashioned, closed in 1935 and the building was listed in 1967
Photograph: Graham Ackroyd

Peter Tompkins, an actuary, has moved into one of the penthouse flats. 'I look out on one side to the train shed, and to Camden town hall on the other,' he says
Photograph: Linda Nylind for the Guardian

The flat, jokes Tompkins, could be described by a prosaic estate agent as a '"two-bedroom maisonette in a converted older property" – but when I tell people my living room has a ceiling 10 metres high, the picture begins to change dramatically'
Photograph: Linda Nylind for the Guardian

Tompkins's flat takes up much of the main entrance tower of St Pancras
Photograph: Linda Nylind for the Guardian

'Has it given me sleepless nights?' says developer Harry Handelsman, founder of the Manhattan Loft Corporation. 'Sleepless weeks and months, actually ... This is a Grade I listed building, a wonderful place – not something that could be converted on the cheap'
Photograph: Graham Ackroyd

Handelsman and hedge fund manager Stanley Fink are stumping up £200m for the conversion
Photograph: Nicholas Kane

The penthouse flats are highly theatrical spaces, with rooms, mezzanines and balconies threaded between spectacular timber roof frames
Photograph: Linda Nylind for the Guardian

The flats sold very quickly, mostly off-plan
Photograph: Nicholas Kane

'We had to dream up ways of adding plumbing, wiring, heating, ventilation, lifts and other modern services, all without being able to cut into a single truss or beam,' says Les Broer, the South African-born architect who has worked on the project for the past dozen years. 'It's been a bit of a jigsaw puzzle'
Photograph: Linda Nylind for the Guardian