Those of you signing up for Google AdWords for the first time, or setting up a brand new account, can not currently use Direct Debit option for payment.
A Google AdWords Help thread has Googler, Bindu confirming this as a known issue. Bindu said it won't be fixed for a few weeks:
We are aware that currently new advertisers signing-up for AdWords are unable to choose Direct Debit as a form of payment. Please note that this payment option is only temporarily unavailable for new sign-ups. We have escalated this to our engineers who’re working to resolve this on high priority.This issue should be resolved in a few weeks. As a workaround, you may choose any other forms of payments.
Forum discussion at Google AdWords Help.
