What's got David Cameron into yet another mess? The simple absence of sunshine on a big pile of cash, that's what.

Whenever people think they can get round rules to hide their ill gotten from disclosure - whether it be by entertaining in your private flat or whether it be by abusing tax law to hide in a Swiss bank account there's one odour that is always to be found - that of potential corruption.

Of course that may not be true. But the stench rises anyway because if it was easy to account for the transaction the need to hide it from view would not arise. And all too often the need to hide does exist.

Last week the Tories signed a deal with the Swiss to assist tax evasion.

This week they're hiding their own business from view.

Both very clearly feel wrong.

That's because they are.

The simple fact is that if something won't stand up under a ray of sunshine, don't do it. It's a lesson Cameron and Osborne have yet to learn.