As a Cabinet Minister he had three outstanding qualities: he worked hard, he carried his proposals through Cabinet and Parliament, and he carried his department with him.1
Winston Churchill was Britain’s greatest prime minister. He was a mature politician when he became prime minister in 1940. His greatness flows from the vast experience which shaped him as a man. He had huge early success the first phase of which ended in the catastrophic failures of Gallipoli for which he paid a severe price. Nonetheless he was brought back into cabinet by a prime minister who understood the importance of not being petty. His final major role ended in 1929 and he entered the political wilderness only emerging in 1940.
Churchill was a Victorian aristocrat born in 1874. He was thirty-one when appointed Under Secretary of State for the Colonies. Churchill entered the cabinet in1908, aged thirty-four, and remained there until 1915 holding four cabinet positions including Home Secretary, 1910-11. As Home Secretary he made the definitive statement of what prison is:
I did my utmost consistent with public policy to introduce some sort of variety and indulgence into the life of their inmates, to give to educated minds books to feed on, to give to all periodical entertainments of some sort to look forward to and to look back upon, and to mitigate as far as is reasonable the hard lot which, if they have deserved, they must none the less endure.2
In 1915 he left the cabinet after the catastrophic Gallipoli campaign in which he was heavily implicated. Aged 41, he rejoined the army serving as a Lt. Colonel leading soldiers in trench-warfare. Churchill’s tremendous personal and political courage was part of his hinterland colouring and informed his political judgement. As an outstanding politician, he returned to cabinet as Minister for Munitions, 1917. He held two more cabinet posts until 1922 when he lost his seat.
Churchill returned to the cabinet in 1924 as Chancellor of the Exchequer, where he remained until 1929. He was 55 years old and had been a senior politician more-or-less continuously for twenty-four years, holding nine ministerial posts. He’d been a senior officer in the First World War and had a unique biography. In 1929 he was at the peak of his powers. He was in the wilderness for a further eleven years before becoming prime minister.
In 1929 it looked as Churchill’s political career was finished. As the 1930s progressed it was increasingly likely that he’d be a What if politician, a major figure stranded on the outside of the political scene. Churchill was literally a warrior and had huge resilience which carried him through the 1930s even though it was far from certain that his time would ever come.
Addendum: The ministerial experiences of prime minsters after Churchill
Clement Attlee (1 – deputy to Churchill during the war); Anthony Eden (4); Harold MacMillan (7); Alec Douglass-Home (4); Harold Wilson (1); Edward Heath (5); James Callaghan (4); Margaret Thatcher (1); John Mayor (5); Tony Blair (0); Gordon Brown (1); David Cameron (0); Theresa May (1); Boris Johnson (1) Since 1979 those becoming prime minister have had significantly less ministerial experience than most of those previously apart from John Major.
1 Winston Churchill in politics, 1900–1939 – Wikipedia
2 Churchill on Prison – Double Aspect Compare this with Chris Grayling, Justice Secretary, who 104 years later effectively banned access to books for prisoners. This was later found to be illegal. Justice Minister Chris Grayling defends prisoner book rules – BBC News