Also money laundring helped plenty, on insanely inflating the prices - money from anyone who could afford this. There are buildings in London that are empty. Kind of like a piece of jewelery that you keep as a safe-keep in the safe (but only bigger).
That said, it is a pitty that plenty of people will see that they got a mortgage of 999 for a flat that "now" costs 200-300,but it is healthy for this parasitic/fraudulent behaviour to end.