January–November – Experimental radio broadcasts including speech and music are made from a studio at the Marconi Company factory in Chelmsford, Essex.
13 May – "Hands Off Russia" campaign: London dockers refuse to load the SS Jolly George with munitions intended for Poland in the Polish–Soviet War.[6]
15 June – Australian soprano Nellie Melba becomes history's first well-known performer to make a radio broadcast when she sings two arias as part of the series of Marconi broadcasts from Chelmsford.
20 June – Five people are killed during severe rioting in Ulster.
24 June – Troops are sent to reinforce the Derry garrison.
Irish-born Roman Catholic Archbishop of Melbourne Daniel Mannix is detained on board ship off Queenstown and prevented from landing in Ireland or from speaking in the main Irish Catholic communities elsewhere in the UK.[11]
Blind Persons Act 1920 passed, the world's first disability-specific legislation, providing a pension allowance for blind persons aged between 50 and 70 years of age, directing local authorities to make provision for the welfare of blind people and regulating charities in the sector.
10 October – It is announced that compulsory hand signals are to be introduced for all drivers. Hand signals will remain a crucial part of motoring life until the 1970s, when the increased use of indicators on vehicles renders them no longer necessary.
14 October – The first women receive degrees at the University of Oxford, these being awarded retrospectively. Dorothy L. Sayers and Ivy Williams are among them.[16]
11 December – Irish War of Independence: the Burning of Cork: British forces set fire to 5 acres (20,000 m2) of the centre of the city of Cork, including the City Hall, in reprisal attacks after a British auxiliary is killed in a guerilla ambush.
