To be fair, they are getting a month's worth of rain in 3 hours.
And, like I said, the typical British response would be "don't be a wally, take a brolly".
Did businesses stop trading ? NO !
Did people not go to work ? NO !
Other than flow-rate changes, did planes cease landing at major airports ? NO !
Did ships stop docking at major ports ? NO !
Did the Prime Minister call a COBRA crisis meeting with senior ministers ? NO !
Business as normal for the UK with the exceptions of the tubes and trains that ceased working. But the British trait that is "flying in the face adversity" ensured that people did their upmost to get to wherever they would normally be (sure it took them a little longer to get there, but hey, it would be the same on a day where tube drivers were on strike).
As I said ... live in Europe or visit a few times before making silly comments about weather "spooking the markets" !