The 25th anniversary of the stock market crash of October 19, 1987, falls due next week and analysts are already starting to run us through what happened, why it happened, what happened next and the risk of it happening all over again.

To recap, the Dow Jones index had been falling the week before the crash following signs of US economic growth softening. But the Black Monday rout actually began in Hong Kong, spreading west to Europe, then Wall Street, immediately as markets opened.