London’s top firms have responded to the threat posed by the expansion of their US rivals into Europe by expanding their own US law practices by more than 20% in the past 12 months, according to research by Legal Week’s sister title Legal Week Global.

American firms’ foothold in the European legal market looks set to come under siege as research in the June issue of Legal Week Global shows London firms expanded their US law practices by more than 20% during the past 12 months.