Cyclist ride bicycles sponsored by Barclays Bank at Camden Lock, in London April 9, 2011. An expected shake-up of Britain's biggest banks to make them safer by ring-fencing their retail arms from riskier trading operations may not be fully effective, lawyers warned on Saturday. Britain's "Big Four" banks - Lloyds, Barclays, HSBC, and Royal Bank of Scotland - have all resisted calls for a radical shake-up of their business. REUTERS/Suzanne Plunkett (BRITAIN - Tags: BUSINESS TRANSPORT TRAVEL ENVIRONMENT)