1820 in the United Kingdom
Events from the year 1820 in the United Kingdom.
- Monarch – George III (until 29 January), George IV
- Prime Minister – Robert Jenkinson, 2nd Earl of Liverpool (Tory)
- 29 January – George IV of the United Kingdom ascends the Throne on the death at Windsor Castle of his father George III (after 59 years on the throne), ending the period known as the English Regency which began in 1811. George IV has served as prince regent during this time due to his father's mental deterioration.
- 30 January – Royal Navy captain Edward Bransfield in the Williams is the first person positively to identify Antarctica as a land mass.
- 23 February – a plot to murder the Cabinet, the Cato Street conspiracy, is exposed.
- March – general election increases Tory party majority.
- 1–2 April – a Proclamation, signed "By order of the Committee of Organisation for forming a Provisional Government", is distributed in the Glasgow area, beginning the "Radical War" in Scotland. The following day, around 60,000 – particularly weavers – stop work across a wide area of central Scotland. Disaffection spreads to the West Riding of Yorkshire.
- 5 April – Radical War: Troops capture radicals at Bonnybridge.
- 8 April – Radical War: Radical prisoners from Paisley are freed from jail in Greenock after militia have killed eight of the crowd.
- 1 May – the Cato Street conspirators are the last to suffer decapitation following their hanging for treason outside Newgate Prison in London.
- 11 May – launch of HMS Beagle, the ship that will take the young Charles Darwin on his scientific voyage, at Woolwich Dockyard.
- June – Pains and Penalties Bill put before Parliament to deprive Caroline of Brunswick, George IV's wife, of the title of Queen Consort. The bill is withdrawn after her public trial.
- 26 July – opening of Union Chain Bridge across the River Tweed between England and Scotland, designed by Captain Samuel Brown. Its span of 449 ft (137 metres) is the longest in the Western world at this time, and it is the first wrought iron vehicular suspension bridge of its type in Britain.
- 30 August – Radical War: Radical leader James Wilson, a Strathaven weaver, is executed for treason on Glasgow Green for his part in the rising.
- 8 September – Radical War: Radical leaders John Baird and Andrew Hardie are executed at Stirling for their part in the rising at Bonnybridge.
- John Keats' collection Lamia and Other Poems.
- Walter Scott's novels The Abbot and The Monastery.
- Percy Bysshe Shelley's lyrical drama Prometheus Unbound.
- The 6th Edition of Encyclopædia Britannica.
- Hone and Cruickshank's satirical work The Queen's Matrimonial Ladder.
- Publication of the last of William Blake's prophetic books, Jerusalem: The Emanation of the Giant Albion, is completed.
- 17 January – Anne Brontë, author (died 1849)
- 28 February – John Tenniel, illustrator (died 1914)
- 30 March – Anna Sewell, writer (died 1878)
- 27 April – Herbert Spencer, philosopher and political theorist (died 1903)
- 4 May – Joseph Whitaker, publisher (died 1895)
- 12 May – Florence Nightingale, nurse (died 1910)
- 23 November – Isaac Todhunter, mathematician (died 1884)
- 10 December – Princess Elizabeth of Clarence (died 1821)
- 23 January – Prince Edward, Duke of Kent and Strathearn (born 1767)
- 29 January – King George III of the United Kingdom (born 1738)
- 1 May – Arthur Thistlewood, conspirator (born 1774)
- 30 May – William Bradley, Britain's tallest ever man (born 1787)
- 19 June – Sir Joseph Banks, naturalist and botanist (born 1743)
- 3 September – Benjamin Latrobe, architect (born 1764)
- 11 October – James Keir, geologist, chemist and industrialist (born 1735)
- William Drennan, poet (born 1754)
- "George IV (1762–1830)". History. BBC. Retrieved 2013-02-27.
- Jones, A. G. E. (1982). Antarctica Observed: who discovered the Antarctic Continent?. Caedmon of Whitby. ISBN 0-905355-25-3.
- Penguin Pocket On This Day. Penguin Reference Library. 2006. ISBN 0-14-102715-0.
- Palmer, Alan; Veronica (1992). The Chronology of British History. London: Century Ltd. pp. 250–251. ISBN 0-7126-5616-2.
- "Notable Dates in History". The Flag in the Wind. The Scots Independent. Archived from the original on 8 August 2014. Retrieved 2014-08-09.
- Drewry, Charles Stewart (1832). "Section III". A Memoir of Suspension Bridges: Comprising The History Of Their Origin And Progress. London: Longman, Rees, Orme, Brown, Green & Longman. pp. 37–41. Retrieved 2011-08-16.