From the City of London website:
During the Second World War the City suffered appalling damage and loss of life. The Cripplegate area was virtually demolished and by 1951 the resident population stood at only 48, with 5,324 in the whole City. Discussions started in 1952 on what sort of redevelopment should take place on the devastated site. Many people involved with the City of London voiced their concern at the dwindling number of residents living within the Square Mile and plans were considered for returning a stable population. A report was presented and the Court of Common Council, of 19 September 1957, accepted as a matter of policy that there should be a genuine residential area created on the site.