London's biggest banks could start leaving the capital within the next few months, according to one of the Square Mile's most important figures.
Anthony Browne, head of the British Bankers' Association (BBA), which represents the interests of UK-based lenders and investment banks, told The Guardian banks have already started contingency planning and the process of moving chunks of business to other EU countries could begin within the next two months.
"Most international banks now have project teams working out what operations they need to move to ensure they can continue serving customers, the date by which this must happen, and how best to do it," Browne said in a column this morning.
He added: "Their hands are quivering over the relocation button. Many smaller banks plan to start relocating before Christmas. Bigger banks are expected to start in the first quarter of the year."
Before the referendum vote a string of financial institutions issued high profile warnings about the possibility of leaving London in order to ensure continued full access to the EU Single Market.
With passporting rights, the EU rules which allow banks to operate smoothly across the entire Single Market as long as they have licenses and are regulated in one country, under threat, Browne insisted: "Businesses can't wait to the last minute [to find out the terms of the Brexit deal]. It takes years to move operations. Banks might hope for the best but have to plan for the worst.
Goldman Sachs have been among those mulling a partial relocation, with 2,000 London jobs potentially being shifted into the rest of the EU. Insurance giant Lloyd's of London is also conducting its own review into whether it needs to open a new branch or division on the continent.
The former journalist, adviser to Boris Johnson and Morgan Stanley lobbyist, also revealed that government-backed "delegations from Frankfurt, Paris, Dublin and Madrid are all coming to the UK to pitch to bankers."
Browne praised the conduct of both the chancellor Philip Hammond and the Brexit secretary, David Davis, but branded the whole process of negotiations to erect new trade barriers "economic irrationality". He also warned the UK could be "talking ourselves into defeat before negotiations have even begun."
The comments come just hours after Theresa May returned from her first EU leaders' summit in Brussels, and with the landmark EU-Canada trade deal on the ropes following the EU's failure to address the concerns of Belgian region Wallonia over some terms of the agreement.