Banks have already begun to take action to shift operations out of the UK, but most of their staff will have to wait several months to find out how many thousands of them will be asked to move to fledgling financial hotspots like Paris, Dublin and Frankfurt.

Investment banks, who donated heavily to the Remain campaign, have reacted immediately to Britain’s referendum result, with some of London’s largest institutions approaching regulators to secure licences and lining up executives to relocate.

The big US banks — JPMorgan Chase, Goldman Sachs, Bank of America, Citigroup and Morgan Stanley — have large operations employing tens of thousands of people in the UK. They have historically set up their regulated businesses in Britain and then used its right to “passport” into the rest of the 28-member bloc.