There is a good chance that an investigation into whether traders at some world's top banks manipulated foreign exchange markets could be worse than the Libor scandal for banks. Royal Bank of Scotland chief executive, Ross McEwan, has said in an interview on Friday.

When asked in an interview with the U.K.'s LBC radio if the investigation into foreign exchange rate-fixing would be more expensive than the rate-fixing or insurance mis-selling scandals, the RBS boss answered "unfortunately it has the hallmarks".