Tough capital rules can give big banks an advantage over their smaller rivals and need reviewing, according to top Bank of England regulator Martin Stewart.
A long campaign by challenger banks - smaller lenders that are trying to take on the giants of the industry - appears to have won concessions from officials, who are now looking to change the rules.
These rules can mean small banks have to set aside more capital against prime mortgages than big banks, which Mr Stewart acknowledged can effectively stop them competing with the high street banks in that market.