Warren Chalk started to use the word 'capsule' in 1964. The Archigram Group at that time formed a part of the Taylor Woodrow Design Group, under Theo Crosby, and it was the habit of the company to feed the Group with experimental projects. The notion of a completely new prefabricated dwelling was one of these: the only constraint was that it should stack up into a tower structure.

From every point of view the space capsule was an inspiration: how different in concept and in efficiency from the tradition of buildings! The statement was a capsule dwelling, with the ergonomics and the sophistication of a space capsule. The parts would be tailored and able to be updated as technology moved forward and as the dweller changed their needs. Simultaneously, the Plug-In City was being developed and, whilst both projects remained quite separate, it soon became obvious that the capsule dwelling would be a preferred type within a Plug-In City. It also became obvious that the wedge-shaped unit sitting into a tower was a limitation of the concept.

The capsule dwelling was a set of components: whilst snugly and efficiently locked together they were capable of total inter­changeability. To use the automobile as an analogy: the Ford floor tray could be traded in for a Chrysler floor tray. There would be a continual exchange taking place, with constantly changing and evolving parts. Perhaps a dream-machine as well as a mere ‘house’? The whole tower would be organised to allow the larger elements to be replaced by crane and the smaller elements manoeuvred from within: as a result all parts could be capable of being opened-out or clipped-in. The main parts were conceived as pressed – metal or GRP – though later the possibility of pressed paper started to interest the Group.

Conceptually, the ‘capsule’ serves to describe an approach to housing by presenting a series of very sophisticated and highly designed elements locked together within a ‘box’ which is itself highly tailored. It is an industrial design approach. It implies a deliberate – even a preferred – lifestyle. It suggests that the city might contain a defined conglomeration of such a lifestyle, rather like a hotel. At the same time it is definitive and would bypass many of the myths of urban design which depend upon hierarchies of incident and the treatment of housing as a folk art.