John Allsebrook Simon, 1st Viscount Simon (1873-1954) was a British politician and statesman. Educated at Fettes College in Edinburgh and Wadham College, Oxford, he became a fellow at All Souls and was called to the bar at the Inner Temple in 1899. Simon became a successful lawyer, and entered parliament as a Liberal representing Walthamstow in 1906. He entered the Government as Solicitor-General in 1910, and advanced in 1913 to Attorney-General, in both cases succeeding Rufus Isaacs. In Asquith's coalition government in May 1915, Simon became Home Secretary, but resigned early the next year in protest against the introduction of conscription.

After Asquith's fall in late 1916, Simon remained in opposition as an Asquithite Liberal until 1918, and once again after 1922. In 1931, when the Liberals split once again, Simon became leader of the National Liberals who supported protectionism and Ramsay MacDonald's Coalition government, and served as Foreign Secretary under MacDonald, and then as Home Secretary and Deputy Leader of the House of Commons under Baldwin and Chancellor of the Exchequer under Chamberlain. Over this time, Simon's National Liberals became hardly distinguishable from the Conservatives. In 1940, Simon was raised to the peerage as Viscount Simon, of Stackpole Elidor in the County of Pembroke, and became Lord Chancellor in Churchill's government, although he did not sit in the War Cabinet. In 1945 Churchill formed a brief peacetime administration but once again excluded Simon from the Cabinet - an unprecedented move in peacetime. With Churchill's defeat in 1945, Simon retired from public life.

|- style="text-align: center;" | width="30%" |Preceded by:
The Marquess of Reading | width="40%" style="text-align: center;" |Foreign Secretary
1931–1935 | width="30%" |Succeeded by:
Sir Samuel Hoare

|- style="text-align: center;" | width="30%" |Preceded by:
Sir John Gilmour | width="40%" style="text-align: center;" |Home Secretary
1935–1937 | width="30%" |Succeeded by:
Sir Samuel Hoare

|- style="text-align: center;" | width="30%" |Preceded by:
Neville Chamberlain | width="40%" style="text-align: center;" |Chancellor of the Exchequer
1937–1940 | width="30%" |Succeeded by:
Sir Kingsley Wood

|- style="text-align: center;" | width="30%" |Preceded by:
The Viscount Caldecote | width="40%" style="text-align: center;" |Lord Chancellor
1940–1945 | width="30%" |Succeeded by:
The Viscount Jowitt