People in the UK will probably better understand what a sort code is and how sort code & account numbers are used for transfers etc, but the question is relevant to anyone I'm sure.
Just to clarify:
Giving someone your sortcode and account number allows them to transfer money to your bank... AFAIK there is no way to draw money out of someone's account.
So do you still need such a high level of security on a site as you would say for credit card numbers etc? Would the same care you take over this data as you would for card numbers?
I ask as a client has requested storing the data in their db - they have no SSL certificate to handle this data, but does that matter? Seeing as all someone could do is transfer you money...? Right?