"Our headcount in the UK over the last couple of years has not gone down but it hasn't gone up either - we have added head count you know on the continent," Solomon told the BBC in Davos.

"But I would say that, over time, if this is resolved in a difficult way or a hard way, it'll have an impact on where we invest and where we put people," he said.

(Reporting by Guy Faulconbridge; editing by Kate Holton)