| 20th January 1986 | The United Kingdom and France announce plans to construct the Channel Tunnel. |
| 28th January 1986 | The STS-51-L Space Shuttle ‘Challenger’ disintegrates seventy-three seconds after launch, killing the entire crew of seven astronauts, including schoolteacher Christa McAuliffe. |
| 19th February 1986 | The Soviet Union launches the ‘Mir’ space station. |
| 13th March 1986 | Irish race mare ‘Dawn Run’ wins the Cheltenham Gold Cup, becoming the first racehorse to complete the Champion Hurdle and Cheltenham Gold Cup double. |
| 31st March 1986 | A fire devastates Hampton Court Palace in Surrey. |
| 17th April 1986 | British journalist John McCarthy is kidnapped in Beirut and three other people are also found dead. McCarthy is eventually released in August 1991. |
| 17th April 1986 | A treaty ends the Three Hundred and Thirty Five Years' War between the Netherlands and the Isles of Scilly. |
| 26th April 1986 | One of the reactors at the Chernobyl nuclear plant explodes in Ukraine, creating the world's worst nuclear disaster. Thirty-one people are killed directly by the incident and many more die from cancer in later years. Several thousand people are exposed to significant amounts of radioactive material, making vast territories in Ukraine and Belarus uninhabitable. |
| 26th May 1986 | The European Community adopts the European flag. |
| 29th June 1986 | Argentina defeats West Germany 3-2 to win the 1986 FIFA World Cup. |
| 23rd July 1986 | Prince Andrew, Duke of York, marries Sarah Ferguson at Westminster Abbey. |
| 7th September 1986 | Desmond Tutu becomes the first black Anglican Church bishop in South Africa. |
| 12th October 1986 | The Queen and Prince Philip, Duke of Edinburgh, visit the People's Republic of China. |
| 27th October 1986 | The Big Bang in the London Stock Exchange abolishes fixed commission charges, paving the way for electronic trading. |
| 6th November 1986 | A British International Helicopters’ Boeing 234LR Chinook crashes 2.5 miles east of Sumburgh Airport, killing forty-five people. This is the deadliest civilian helicopter crash on record. |
| 22nd November 1986 | Mike Tyson wins his first world boxing title by defeating Trevor Berbick in Las Vegas. |
| 23rd December 1986 | ‘Voyager’ completes the first non-stop circumnavigation of the earth by air without refuelling. The journey is completed in nine days, three minutes and forty-four seconds. |
| 29th December 1986 | Former Prime Minister Harold Macmillan (b. 1894) dies. |