London banks are warning the government might have left it too late to convince them to stay in the UK after Brexit. and  executives are 'increasingly pessimistic' a transitional deal can be agreed before they start moving staff reports The Week.

Top executives at five of the City's largest lenders told Reuters that any transitional deal to soften the blow of leaving the EU will probably only come towards the end of negotiations, by which point they will be relocating staff abroad.

James Bardrick, UK head of US bank Citi, said the government has been too slow to strike early deals with Europe and banks will have to be ready by September 2018.

"There's been a lot of talk and not a lot of action for a long time. I am anxious it is all a bit late," he said.

Chancellor Philip Hammond has called for the UK to push for a transitional deal to help business, but many banks have been alarmed at the lack of engagement from Whitehall since last year's referendum The government held its first high-level Brexit meeting in months with corporate leaders last week.

Mark Carney, governor of the Bank of England, has previously admitted banks will have to begin relocating activities as early as this September, due to the time it takes to set up new buildings, get licences and hire or move staff.