There is a link to an article about it, in my sig... although it's here if you have them turned off.
Here's the conclusion of that article (highlights mine):
"By 2004, residential real estate in Tokyo was only worth of 10% of its late 1980s peak, while the most expensive land in Tokyo’s Ginza business district had fallen back to just 1% of its 1989 level in the same year (Barsky, 2009). Similarly, the Nikkei stock index is now trading around 10,000, just little over a quarter of its all-time high. It has been over two decades since the popping of Japan’s economic bubble and the country is still actively battling with deflationary forces that are so powerful that near-zero interest rates (zero-interest rate policy or ZIRP), repeated bouts of quantitative easing (some call it “money printing”) and constant Yen-weakening currency interventions have barely made a dent."
Seems like the Japanese government did near-zero interest rates and QE... and it "barely made a dent."
I'm not sure London is the same (obviously there are differences)... BUT it shows that insanely inflated property prices aren't guaranteed to stay forever.