This happened just after the Great Storm of 1987 which hit the UK on the 15th-16th October. Wikipedia has the following slightly unbelievable snippet: "Followi

This happened just after the Great Storm of 1987 which hit the UK on the 15th-16th October. Wikipedia has the following slightly unbelievable snippet: "Following the storm few dealers made it to their desks and stock market trading was suspended twice and the market closed early at 12.30pm. The disruption meant the City was unable to respond to the late dealings at the beginning of the Wall Street fall-out on Friday 16 October, when the Dow Jones Industrial Average recorded its biggest-ever one-day slide at the time, a fall of 108.36. City traders and investors spent the weekend, 17–18 October, repairing damaged gardens in between trying to guess market reaction and assessing the damage. 19 October, Black Monday, was memorable as being the first business day of the London markets after the Great Storm.