1804 in the United Kingdom explained

Events from the year 1804 in the United Kingdom.

Incumbents

January – flounders on patrol off Scotland, apparently striking the Inchcape rock, with the loss of all 491 on board.^[1]
3 January – Hammersmith Ghost murder case.
21 February – The Cornishman Richard Trevithick's newly built "Penydarren" steam locomotive operates on the Merthyr Tramroad between Penydarren Ironworks in Merthyr Tydfil and Abercynon in South Wales, following several trials since 13 February, the world's first locomotive to work on rails.^[2]
7 March
- John Wedgwood founds the Royal Horticultural Society^[3] as the Horticultural Society of London. Another founding member, William Forsyth, dies on 25 July.
- Thomas Charles is instrumental in founding the Bible Society.^[4]
2 April – Forty merchant vessels are wrecked when a convoy led by HMS Apollo runs aground off Portugal.
5 April – High Possil meteorite, the first recorded meteorite to fall in Scotland in modern times, falls at Possil.
26 April – Henry Addington resigns as Prime Minister.
10 May – William Pitt the Younger begins his second premiership as Prime Minister.
12 December – Spain declares war on Britain.
21 December – Rochdale Canal opens, the first to cross the Pennines.^[5]

Construction of Martello towers to protect the coasts of south east England and Ireland against the threat of French invasion is begun, together with (from 30 October) the Royal Military Canal.^[6]
Marlborough White Horse cut in Wiltshire.
William Blake writes including the poem And did those feet in ancient time.^[7]
William Wordsworth writes I Wandered Lonely as a Cloud.^[7]
Dr Joseph Mason Cox publishes Practical Observations on Insanity; in which some suggestions are offered towards and improved mode of treating diseases of the mind, and some rules proposed which it is hoped may lead to a more humane and successful method of cure.^[8]

Early February – James Bronterre O'Brien, Irish-born Chartist leader, reformer and journalist (died 1864)
4 April – Andrew Nicholl, Irish-born painter (died 1886)
20 July – James Kay-Shuttleworth, educationist (died 1877)
14 September – John Gould, ornithologist (died 1881)
6 November – Benjamin Hall Kennedy, Latin scholar and promoter of women's higher education (died 1889)
21 December – Benjamin Disraeli, Prime Minister (died 1881)

Book: Hepper, David J.. 1994. British Warship Losses in the Age of Sail, 1650–1859. Jean Boudriot. Rotherfield. 0-948864-30-3.
Book: Rattenbury, Gordon. Lewis, M. J. T.. Merthyr Tydfil Tramroads and their Locomotives. 2004. Railway and Canal Historical Society. Oxford. 0-901461-52-0.
Book: Penguin Pocket On This Day. Penguin Reference Library. 0-14-102715-0. 2006.
Web site: Our timeline. Bible Society. 2010-11-26. https://web.archive.org/web/20101228224810/http://www.biblesociety.org.uk/about-bible-society/history/our-timeline/. 28 December 2010. dead.
Book: Hadfield, Charles. Charles Hadfield (historian). Biddle, Gordon. The Canals of North West England, vol. II. Newton Abbot. David & Charles. 1970. 0-7153-4992-9. 274.
Lowry, Bernard (2006). Discovering Fortifications: From the Tudors to the Cold War. Shire Publications.
Web site: Icons, a portrait of England 1800-1820. 2007-09-10. https://web.archive.org/web/20071017042835/http://www.icons.org.uk/theicons/icons-timeline/1800-1820. 17 October 2007 .
Book: Cox, Joseph Mason. Practical Observations on Insanity. 2nd. 1806. London. Baldwin. Wellcome Collection. 2023-07-30. .