Throughout the twentieth century due to increasing numbers of staff, the building became more and more cramped until in the 1960s there were calls for the building to be demolished to make way for a bigger building.
However as a result of public outcry, in 1970 the Foreign Office became a Grade I listed building, securing its survival and in 1978, the Home office moved to a new building, easing overcrowding. Subsequently the building underwent a £100 million restoration lasting 17 years, and today remains one of London's most magnificent buildings.