Goldman Sachs is reaching a point in its Brexit contingency planning where it will have made irreversible moves out of the UK, the bank’s chief executive has said.

Lloyd Blankfein told the BBC that Goldman Sachs had rented about ten floors of office space in Frankfurt because he estimates that is the amount the bank will need to house its increased headcount in the German financial hub.

In an interview at the World Economic Forum in Davos, Mr Blankfein said he couldn’t be certain that all of the space would be needed, however Goldman Sachs had “no choice” but to obtain it and begin fitting it out. The US investment bank has also hired people who can transition its contractual agreements with clients from UK law to German law.

“There’s not one month where it’s all or nothing, but every month incremental steps are being taken and at some point we are going to do things that are not going to be undone,” Mr Blankfein said.

He added: “Will it ultimately prove necessary to have done those things? I’m not sure but we can’t get that all done in the last minute.”

“Once we start to repaper – which is very cumbersome because it involves lots of lawyers on both sides and takes months – once we start that, are we going to go back? Probably not,” Mr Blankfein said.

“We’ve already done some and we have told our clients that more is coming,” he said.

The comments underline the potential damage to the UK financial services industry that uncertainty around the nature of a future Brexit deal could do.

Mr Blankfein’s comments come a day after JPMorgan chief executive Jamie Dimon said that the company may have to cut more than 4,000 British jobs if the UK doesn’t secure a Brexit deal that is close to existing arrangements.

The Chancellor Philip Hammond told an audience in Davos this week that the UK will refuse to sign a Brexit trade deal with the European Union unless financial services are included in it.

Mr Hammond said a deal that did not include financial services, which account for roughly 7 per cent of the UK economy and support one million jobs, would not be “fair”.