The government was planning to do tax cuts (further increasing demand during a period of already-high inflation) when the central bank was trying to get inflation under control. The market saw the writing on the wall and people began selling off UK currency, causing the value of the pound to plummet. The central bank had to reverse course and decrease rates to prop up the pound in the short term to stabilize the economy. Ultimately the PM fired her economic minister and then she was ultimately forced to resign herself. This situation was unprecedented anywhere globally as far as I'm aware.