JPMorgan chairman and chief executive, Jamie Dimon, warned that Brexit could force the US banking giant to shift all functions currently serving Europe from the UK across to the continent.

Dimon said that the US bank will see costs spiral as JPMorgan is forced to duplicate functions in both the City and a European location and that “few winners are likely to emerge from this fragmentation” as major European cities including Dublin, Frankfurt, Paris and Amsterdam make a grab for London's long-held dominance in financial services.