By Sudip Kar-Gupta LONDON (Reuters) - Credit rating agency Moody's downgraded Britain's part-nationalized banks Lloyds and Royal Bank of Scotland on Friday, although Britain's finance minister said UK banks were well-placed to cope with a European debt crisis. The cuts to RBS and Lloyds formed part of a broader downgrade of 12 British financial companies by Moody's, which had already been flagged by the agency earlier in the year. Moody's cut RBS by two notches to A2 from Aa3, and downgraded Lloyds TSB by one notch to A1 from Aa3.