Ratings agency Standard & Poor's downgraded a number of UK and German banks including Barclays, Royal Bank of Scotland, Deutsche Bank and Commerzbank, saying it was uncertain whether their respective governments would bail them out if they ran into difficulties."We now consider the prospect that the UK and German governments would provide extraordinary support to their banking systems to be uncertain, meaning that we now include no such uplift in the ratings on systemic commercial banking groups domiciled in these countries," it said.S&P downgraded the counterparty credit rating of Barclays by one notch to 'A-', while Deutsche Bank and RBS were cut to 'BBB' from 'A' and 'A-', respectively. S&P cut Commerzbank to 'BBB+' from 'A-'.Deutsche Bank's credit rating is now only three notches above junk.S&P cut its outlook on Deutsche Bank, Barclays and RBS to 'stable' and Commerzbank to 'negative'.