Regional seats of government or RSGs were the best known aspect of Britain's civil defence preparations against nuclear war. In fact, however, naming conventions changed over the years as strategies in Whitehall changed.
In the aftermath of the nuclear attack on Hiroshima and the Soviet Union's development of the atom bomb, it was clear that London could not survive a nuclear bombardment. Although considerable effort still went into secret construction of military citadels under London, the solution was to disperse the machinery of government into small pieces in the provinces, where there would be a greater chance of survival.
Experiments along these lines had taken place during the Second World War, when a system of regional commissioners existed and key departments were moved out of London to Bath, Harrogate and Cheltenham, among others. However, the idea of a regional commissioner dated back to the First World War and the 1926 general strike.