The young practice saw off competition in the shape of Tyler Hayhurst Architects and BCA London, picking up a £2,000 cheque in the process.
The three firms were asked to present a theoretical pitch to a panel of judges which included two Maggie's Centre representatives, developer Roger Zogolovitch of Land Estates and architects Richard Rogers, Jane Duncan of Jane Duncan Architects, and Eric Guibert of Sens.
The brief asked an initial 40 firms how they would 'add value' to a Maggie's Centre, and the three finalists gave a presentation yesterday at a small-practice conference called Guerilla Tactics.
Featherstone's presentation clearly stood out from the competitors, and the competition win should see the practice's reputation shoot up, following endorsement from the likes of Richard Rogers.
Sarah Featherstone said: 'It was quite nerve-wracking. I'm used to presenting to a panel of seven or eight, but presenting to 250 people was a bit different. It's great to win, and the feedback we got was really useful.'