Reuters reports that industry officials said that a trade deal between Britain and the European Union would help open the door to cross-border financial services from January and avoid years of acrimony. Financial services are not part of talks that continue this week in a bid to conclude a free trade agreement (FTA) before Britain's access to the bloc under transition arrangements ends next month.

"It's very important for the financial services industry that there is a deal, it will completely change the atmosphere," Nicolas Mackel, CEO of Luxembourg for Finance, told.

"If there were to be no deal, relations would be acrimonious for at least one or two years, and it would be very difficult to envisage any bridges to be built across the Channel," he said.