Lord Myners, former City minister, in competition call

LLoyds merged with HBOS during the depths of the financial crisis in October 2008, and was later rescued by the Government, which owns 41 per cent of the group. RBS was also propped up by the former Labour government that month.

"The future lies in less monolithic institutions, with more fluid entries into and out of the banking sector," Lord Myners said. "In practice, the banking commission must therefore give proper consideration to splitting one or both of Lloyds Banking Group and the Royal Bank of Scotland."

The coalition Government appointed the Independent Commission on Banking this summer – a panel of five heavyweight former bankers and other professionals – to assess whether its banks are too powerful and how to boost competition.

Lord Myners said it would take too long for new entrants to change the banking industry's concentration because of the dominance of Britain's six biggest banks in current accounts. I am told neither group has irreversibly integrated their systems, so demerging is possible," he added.