US banks Goldman Sachs and Citigroup and Swiss banks Credit ­Suisse and UBS are understood to be considering a relocation of London staff

At least seven international banks based in London have taken the decision to open offices in Frankfurt to beat trading restrictions in the wake of Brexit, the German city said yesterday.

A further 20 banks were in advanced talks on relocating some staff, Frankfurt officials said, as Deutsche Bank warned it might have to move up to 4,000 of its 9,000 UK employees.

The US giants Goldman Sachs and Citigroup and Swiss banks Credit Suisse and UBS were all understood to be considering a relocation of London staff, German media reported.

More than 250 foreign banks operate in the UK while Frankfurt hosts about 60, including small outposts for the four floated as candidates for relocation yesterday. Frankfurt is keen to position itself as the