Q. When is a business most likely to open a new bank account?
A. When they are first starting out.
Recognizing that the best time to get their foot in the door at a business is before the doors even open, Barclays Bank (UK), addresses the issue front and center on its small business banking home page Barclays Small Business Banking : Small Business.
The company offers a number of startup service including complimentary consultations with business advisors and fee-free checking accounts (18 months if you also bank personally at Barclays, 12 months otherwise).