Recapitalizing banks from the bare cupboard?

Cameron, in this morning's FT, and Osborne, on the AM programme yesterday, have suggested that the government might help recapitalize the UK's banks with government money - a scheme that would cost in the hundreds of billions of pounds.  But only a week ago I sat in the hall in Birmingham and listened to Osborne rule out the sort of borrowing-funded tax cut I have recommended on the grounds that "the cupboard is bare".  So which is it - is the cupboard bare, or do we have hundreds of billions of pounds available to recapitalize the banks?  And if, in fact, the cupboard is not bare (which it is not), then why does Osborne think that spending the money recapitalizing the banks is a superior strategy to saving the money and employing it, later, in a huge tax rebate-based fiscal injection?