Why the banks will not leave the UK.

We hear all the time that if the UK government were to increase controls and limit bank's activities they would leave the UK, what nonsense.
What lunatic country would accept the enormous risks that comes withn having a large banking sector without enforcing real effective controls on these banks activities.
We've been bankrupted by these robbers once already, never again.
Fool me once shame on you, fool me twice shame on me!