London's reputation as a world leading financial centre is expected to be damaged with news emerging that two former employees of a major US bank are set to be arrested this week for fraud.
The pair are suspected of concealing a 4 billion pound trading loss from JPMorgan's UK base in Canary Wharf.
The Royal Bank of Scotland reported a first quarter pre-tax profit of £826 million earlier this month.
The bank's chairman Sir Philip Hampton said he expected RBS, which is partly owned by the taxpayer, to return to the private sector in just over a year.
Boris Johnson has branded the EU's proposed bonus cap a "deluded" and "self-defeating" policy.
The Mayor claims that limiting bonuses to a maximum of twice a banker's salary will only serve to boost financial centres outside the EU.
He said: "People will wonder why we stay in the EU if it persists in such transparently self-defeating policies. Brussels cannot control the global market for banking talent. Brussels cannot set pay for bankers around the world.
"The most this measure can hope to achieve is a boost for Zurich and Singapore and New York at the expense of a struggling EU. This is possibly the most deluded measure to come from Europe since Diocletian tried to fix the price of groceries across the Roman empire."