Sandy and Sally Rendel designed and built the house to fit in the alley, which was almost the exact size 🔑 of a London Underground carriage, alongside their own home in Peckham.

"The major challenge was to tease spaces that were both 🔑 functional and delightful out of space that is no bigger than a tube carriage," said Sandy Rendel, founder of Sandy 🔑 Rendel Architects.

"To commit to the investment involved in developing it we wanted to be sure that the house would not 🔑 simply 'work' but actually be enjoyable to live in," he told Dezeen.

The architects designed the two-storey house to make as 🔑 efficient a use as possible of the narrow site, while creating a space that would be a bright and pleasant 🔑 place to live in.

To avoid placing any weight on the neighbouring buildings the house was constructed using a prefabricated, lightweight 🔑 steel frame, which was expressed internally to maximise the space.