It is perfectly true that the manner in which certain governments hyped up "the dream of home ownership" helped blow up a dangerous bubble in borrowing. But the root cause of the financial meltdown? Sorry, but that's nonsense.

It is important to remember that this crash is much bigger than a typical bust brought about by widespread bad lending. If it were a normal bust, it would be relatively straightforward for policymakers to neutralise by injecting liquidity into the markets and taking over those banks most exposed. But the unprecedented scale and stubbornness of the present crisis of confidence in capital markets is a result of something new.

In recent years, bankers began chopping up bad loans and packaging them into complex, high-yielding securities. These packages were then sold into the international financial system as rock-solid investments. The bankers argued that they had invented an ingenious new way of making money. In reality, they were poisoning the system with dodgy debt.

And here's the real killer. Such is the complexity of these securities that, now they have gone bad, no one can now be sure where the losses lie, or even how big they are. That is why the banks are not lending to each other, except at punitive rates of interest. And because the banks have stopped doing their job of providing credit to the wider economy, the rest of us are suffering.

That, in a nutshell, is the story of the credit crunch. Politicians are certainly not blameless. They should have kept a closer eye on what the cowboys of the City and Wall Street were up to. But for the real culprits, look to those who corrupted the credit system with these opaque securities: bankers.