I think you've got it backwards. If no one is buying and everyone is selling, the value drops. The central bank couldn't sell back the pounds it had bought, and

I think you've got it backwards. If no one is buying and everyone is selling, the value drops. The central bank couldn't sell back the pounds it had bought, and couldn't feasibly keep buying more forever. And, well, no one else would buy pounds in the fixed range: * The currency spent the morning dropping in value. * This despite the government buying up pounds. * There had been news stories about possible devaluation of currencies in the ERM, and suggestions it will be the pound * The country was in recession - the government has limited flexibility with interest rates. Against this backdrop, who would buy pounds? Essentially, as the article notes, it was already a matter of when the pound would drop, not if. Soros' Quantum Fund and other funds might have made it happen a bit sooner, but it was pretty clear that the pound was overvalued.