UK banks are "preparing for the worst" amid fears they will lose talented staff after Brexit, a banking chief has said.
Standard Chartered chief executive Bill Winters said that banks were "preparing for the worst" when Britain quits the bloc, with his own institution spending millions on expanding a base in Frankfurt in case it needs to move staff and operations from London.
But he made it clear that it was not too late to strike a deal which would persuade banks to ditch contingency plans and flush the money spent on proposed relocations "down the toilet", if they were enabled to carry on with their existing business in the UK.
Decisions would be driven by whether UK-based banks are allowed to keep their "passporting rights", which allow them to sell products into the EU without barriers, after Brexit, he said.
Speaking to the BBC, Mr Winters said: "London will take hits in the context of Brexit.
"Some jobs will move from London to the continent.
"I think big parts of the euro-denominated corporate banking business will be forced into Europe.
"It's possible that through the Brexit negotiations that there is some sort of extended passporting rule, but none of us are expecting that quite frankly, or preparing for that.
"We have to prepare for the worst. Our regulators in the UK require us to prepare for the worst.
"The best would be we carry on as we are and passporting is allowed to continue to exist and we can run our business as we do today, in which case we will have spent a bunch of money and flushed it down the toilet."
Asked if he meant that his bank would be willing to mothball its new facilities in Frankfurt, despite the large sums already spent, he replied: "That's correct."
Despite official insistence that the UK wants to continue to attract the brightest and the best from around the world, Mr Winters said that "body language" from the Government was already putting off talented workers from settling here.
"We have already had some setbacks for the talent pool in London through the restriction on student visas. That's already a problem," he said.
"Some of the best talent that we can have in the UK marketplace is coming from students that have chosen to study here and then stayed for some extended period afterwards.
"We've noticed that impact already, more through a sense from non-UKs or foreigners that this might not be such a hospitable place any longer.
"It's more psychological than contractual, as it were.
"But I think it's something we must really be very careful about."