In the interwar and postwar periods in Britain the view amongst academics and the political elite was that Britain’s unwritten constitution worked well. Two sets of ideas underpinned this; the Whig view of history and the Westminster model
The Whigs were the mildly reformist group that developed in Parliament in the late 17th century.
They believed in limiting the power of the Monarch and in religious toleration towards the groups of the population.
By the end of the 18th century, were more sympathetic towards electoral reform, tolerance towards Catholics and the ideals of the French Revolution. They had the support of urban business and commercial groups while their rivals, the Tories, tended to represent the landowners.
Writers in the Whig tradition, especially Macaulay, saw Britain as a successful State slowly modernising and becoming more democratic and adapting to change in a pragmatic and non-ideological way and argued that the unwritten and flexible British constitution was an important part of this success.
Dicey in his 1885 book Introduction to the Study of the Law of the Constitution sets out the ways in which the Constitution is meant to work and argued that the gradual development, case by case, of individual rights by judges was more successful than abstract statements in written constitutions.
Politicians also argued that the Constitution worked well and former Prime Minister Clement Attlee in his book on the British system in the 1950s saw the Constitution as near perfect.