|Covid-19|Monarch — Victoria
Prime Minister — The Viscount Palmerston (Liberal) (until 18 October), Lord John Russell (Liberal) (starting 29 October)
April — Official opening of Crossness Pumping Station, a major landmark in completion of the new London sewerage system designed by Joseph Bazalgette for the Metropolitan Board of Works.
28 May — The Mimosa sets sail, carrying Welsh emigrants to Patagonia.
June — Jumbo, a large African elephant, is transferred to London Zoo and becomes a popular attraction.
4 June — The lyrics of the hymn "Onward, Christian Soldiers", written by Sabine Baring-Gould as "Hymn for Procession with Cross and Banners", are first sung by children processing to St Peter's Church, Horbury, in the West Riding of Yorkshire.
9 June — Staplehurst rail crash in Kent: 10 killed, 49 injured; Charles Dickens is amongst the survivors.
25 June — James Hudson Taylor founds the China Inland Mission at Brighton.
29 June — New Poor Law Act improves conditions in workhouses.
July — General election won by the Liberal Party led by Lord Palmerston.
2 July — The Christian Mission, later renamed The Salvation Army, is founded in Whitechapel, London by William and Catherine Booth.
4 July — Lewis Carroll publishes his children's novel Alice's Adventures in Wonderland (first trade edition in December).
5 July — First speed limit is introduced in Britain by the Locomotive Act — 2 mph in town and 4 mph in the country.
14 July — A party led by Edward Whymper makes the first ascent of the Matterhorn.
23 July — The SS Great Eastern departs on a voyage to lay a transatlantic telegraph cable.
September — John Henry Walsh (writing as 'Stonehenge' in the magazine The Field) gives the first definition of a dog breed standard (for the pointer) based on physical form.
28 September — Elizabeth Garrett Anderson graduates as Britain's first woman doctor.
9 to 20 October — Unsuccessful uprising against British rule in Morant Bay, Jamaica; 400 rebels executed.
29 October — Lord John Russell becomes Prime Minister following the death of Lord Palmerston on 18 October.
6 November — American Civil War: Surrender to HMS Donegal at Liverpool of the Confederate commerce raider CSS Shenandoah.
11 November — Duar War with Bhutan ends with the Treaty of Sinchula, in which Bhutan cedes control of southern passes to Britain in return for an annual subsidy.
26 November - Lewis Carroll, an author from Daresbury, Cheshire, publishes Alice in Wonderland, as per request from Alice Liddell
16 December — Edward John Eyre, governor of Jamaica, dismissed and censured for his excessive actions during the suppression of the recent rebellion.
Francis Galton formulates eugenics.
James Clerk Maxwell publishes A Dynamical Theory of the Electromagnetic Field.
Joseph Lister discovers the sterilising effects of carbolic acid.
Major outbreak of rinderpest in British cattle.
Hong Kong and Shanghai Banking Corporation founded in Hong Kong by Thomas Sutherland.
Gladiateur wins the English Triple Crown by finishing first in the Epsom Derby, 2,000 Guineas and St Leger.
Lewis Carroll's novel Alice's Adventures in Wonderland.
Charles Dickens' novel Our Mutual Friend (publication concludes).
Robert Smith Surtees' novel Mr. Facey Romford's Hounds (posthumous).
A. C. Swinburne's narrative poem Atalanta in Calydon.
Anthony Trollope's novel Can You Forgive Her? (publication concludes).
9 April — Adela Florence Nicolson ('Laurence Hope'), poet (suicide 1904)
2 June — George Lohmann, cricketer (died 1901)
3 June — Prince George of Wales, later George V (died 1936)
15 July — Alfred Harmsworth, 1st Viscount Northcliffe, newspaper and publishing magnate (died 1922)
12 October — Arthur Harden, chemist, Nobel Prize laureate (died 1940)
20 October — Sir Rhys Rhys-Williams, 1st Baronet, judge (died 1955)
27 October — Tinsley Lindley, footballer (died 1940)
4 December — Edith Cavell, nurse (executed 1915)
30 December — Rudyard Kipling, writer, Nobel Prize laureate (died 1936)
6 February — Mrs Isabella Beeton, writer on household management and cookery (born 1836)
11 March — Robert Hermann Schomburgk, explorer (born 1804 in Freiburg)
2 April — John Cassell, publisher and entrepreneur (born 1817)
30 April — Robert FitzRoy, meteorologist and admiral (born 1805; suicide)
27 May — Charles Waterton, naturalist and explorer (born 1782)
8 June — Joseph Paxton, gardener and architect (born 1803)
25 July — Dr James Barry, military surgeon, revealed on death to be a woman, probably Margaret Ann Bulkley (born 1789-1799)
12 August — William Jackson Hooker, botanist (born 1785)
9 September — William Henry Smyth, astronomer and admiral (born 1788)
18 October — Viscount Palmerston, Prime Minister (born 1784)
1 November — John Lindley, botanist (born 1799)
8 November — Thomas Sayers, boxer (born 1826)
12 November — Mrs Elizabeth Gaskell, novelist and biographer (born 1810)
1865 in the United Kingdom Wikipedia
Events from the year 1865 in the United Kingdom.