William Philip Sidney, 1st Viscount De L'Isle (23 May 1909 - 5 April 1991), 15th Governor-General of Australia, was the last British Governor-General. He was the son of the 5th Baron De L'Isle and Dudley, and came from one of England's oldest and most distinguished families. He was educated at Eton and Cambridge and became a chartered accountant. In 1929 he joined the Grenadier Guards Reserve of Officers. During World War II he served in France and Italy. He led a handful of men in the defence of the Anzio beachhead, for which he was awarded the Victoria Cross.
In 1944 he was elected unopposed to the House of Commons as Conservative MP for Chelsea. His father died in 1945 and he went to the House of Lords as the 6th Baron De L'Isle. In 1951 he was appointed Secretary of State for Air under Winston Churchill and held that office until 1955. During this time he visited Australia, travelling to Woomera to examine weapons research and meeting Prime Minister Robert Menzies, who was later to appoint him Governor-General. In 1956 he was created Viscount De L'Isle.
In 1961 De L'Isle was appointed Governor-General of Australia following the sudden death of Lord Dunrossil. He performed his ceremonial duties with dignity and travelled widely around Australia. There were no political or constitutional controversies during his term, since the Liberal government of Robert Menzies was firmly in power.
By the time of De L'Isle's retirement in 1965 public opinion was strongly in favour of an Australian Governor-General, although this was not a reflection on his performance in the role. His continuing interest in Australia was shown by several visits after his retirement, the last for Australia's bicentenary in 1988, when he presented a bronze statue which now stands in the grounds of Government House in Canberra. He died in Britain in April 1991.
| Preceded by: Viscount Dunrossil | Governors-General of Australia | Followed by: Lord Casey |
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|width="30%" align="center"|Preceded by:
New Creation
|width="40%" align="center"|Viscount De L'Isle
|width="30%" align="center" rowspan="2"|Followed by:
Philip Sidney
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|width="30%" align="center"|Preceded by:
William Sidney
|width="40%" align="center"|Baron De L'Isle
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