London may have clung on to its mantle as the world's top financial centre, but scratch beneath the surface and it doesn't take long to find signs of a brain drain from the UK capital as the war for financial talent lures staff where the money is - which is increasingly overseas.

A striking survey from recruitment firm Sheffield Haworth reveals that no less than 37% of external hires for roles in financial services in the Middle East and north Africa were staff moving from London or the US last year, while 31% of Asia Pacific hires moved from either London or the US.