1720 in Great Britain

Incumbents

• Monarch – George I

Events

• 10 February – Edmond Halley is appointed Astronomer Royal by George I
• 17 February – Treaty of The Hague signed between Britain, France, Austria, the Dutch Republic and Spain ending the War of the Quadruple Alliance.
• April – "South Sea Bubble": A scheme for the South Sea Company to take over most of Britain's unconsolidated government debt massively inflates share prices.
• 15 April – Ralph Allen of Bath is appointed to farm Cross and Bye Posts, leading to his reform of the system.
• 23 April – George I publicly reconciles with his son George, Prince of Wales at St James's Palace
• 1 June – British silversmiths are once again allowed to use sterling silver after 24 years of being limited to a purer Britannia silver.
• 11 June
• * Robert Walpole and his ally and brother-in-law Charles Townshend rejoin the government as Paymaster of the Forces and Lord President of the Council ending the Whig Split lasting since 1717. Within a year they will be Prime Minister and Northern Secretary respectively.
• * Parliament approves the Bubble Act, prohibiting the formation of joint-stock companies except by royal charter.
• 25 June – "South Sea Bubble" reaches its peak as South Sea Company stock is priced at £1,060 a share.
• 12 July – Under authority of the Bubble Act, the Lords Justices attempt to curb some of the excesses of the stock markets during the "South Sea Bubble". They dissolve a number of petitions for patents and charters, and abolish more than 80 joint-stock companies of dubious merit, but this has little effect on the creation of "Bubbles", ephemeral joint-stock companies created during the hysteria of the times.
• September – "South Sea Bubble": share prices, led by those of the South Sea Company, collapse.
• 16 November – Pirate captain John Rackham is brought to trial at Spanish Town in Jamaica; he is hanged at Port Royal two days later. Most of his crew is also hanged but female pirates Mary Read and Anne Bonny are spared.
• 29 December – Haymarket Theatre opens in London.

Publications

• Richard Mead's treatise A Short Discourse concerning Pestilential Contagion, and the Method to be used to prevent it.

Births

• 13 January – Richard Hurd, bishop and writer
• 27 January – Samuel Foote, dramatist and actor
• 9 March – Philip Yorke, 2nd Earl of Hardwicke, politician
• 8 May - William Cavendish, 4th Duke of Devonshire, Prime Minister
• 18 July – Gilbert White, naturalist and cleric
• 18 August – Laurence Shirley, 4th Earl Ferrers, murderer
• 30 August – Samuel Whitbread, brewer and politician
• 31 December – Charles Edward Stuart, pretender to the British throne

Deaths

• 31 January – Thomas Grey, 2nd Earl of Stamford, privy councillor
• 20 April – George Gordon, 1st Earl of Aberdeen, Lord Chancellor of Scotland
• 5 August – Anne Finch, Countess of Winchilsea, English poet
• 9 August – Simon Ockley, orientalist
• 18 August – Matthew Aylmer, 1st Baron Aylmer, admiral
• 18 November – John Rackham, pirate