In January 1933, Reginald Sassoon, amateur jockey son of the philanthropist Mozelle Sassoon, was killed at Lingfield. In his memory, his mother decided to commission a block of workers' flats, an idea which may have stemmed from a new acquaintance. This was Elizabeth Denby, who was just embarking on her career as one of the century's most important housing reformers, and was keen to find a 'live' project through which she could realise her vision of well-planned, well-equipped housing, with extensive amenities, all expressed in a new architectural language. Already collaborating with Max Fry on design ideas, they took the project to the doctors (Innes Pearse and George Scott Williamson) behind the Peckham Experiment, who were then developing the site on St Mary's Road as the purpose-built Pioneer Health Centre.

Denby and the doctors had much in common. They all believed that modern urban life had broken up traditional communities and environments, something that had grave implications for the nation's physical and corporate health. Crucially, rather than seeing reformed suburbs or garden cities as the solution to urban devitalisation, as they called it, our Peckham reformers insisted on the transformation of the city itself. Through architectural interventions they sought to make 'a full and energetic life possible in terms of urban existence.' The Centre and the flats were component parts of just such an enabling environment, the basis for a 'genuine urban life.'

The Centre was the focus around which individual families could gather and cohere into a community; it provided extensive leisure facilities as well as health care, amenities which enabled them, in the doctors' parlance, to be 'brought to health' and become active citizens (as well as producing healthy babies; there was a strong element of positive eugenics about the Centre). Sassoon House offered a complementary ultra-modern domestic setting - better-equipped than anything suburbia could offer and at an affordable weekly rent.

R.E.Sassoon House had twenty flats: three three-roomed (for 11s rent) and one four-roomed (at 9s 2d rent) per floor. Access was by galleries which were reached from the staircase tower. This was lit by a curtain wall of plate glass decorated with a vitrolite glass mural of a horse and rider by Hans Feibusch. Originally, a wall ran north between the tower and the perimeter wall to create a private yard for the tenants, which contained pram and bike sheds, a bench and drying rails.

Here, for the first time in workers' housing in Britain, Denby and Fry introduced the 'existenz-minimum' plan, a technique to use the minimum space for family life as efficiently as possible in order to keep building costs down, as well as provide a labour-saving working environment for the housewife (both Centre and flats were informed by a desire to re-establish gender roles in the family, something contemporary unreformed urban life was blamed for disrupting).