Financial services world-wide would be worse off if European Union leaders are successful in their efforts to repatriate the clearing of euro-denominated derivatives, the founder and chief executive electronic trading firm NEX Group has warned.

Michael Spencer told an audience of academics and business professionals at the Prosperity UK conference in London that an effort to shift London's euro-denominated clearing business back to the European Union would penalise the Europeans and leave London, Europe and "the whole financial structure worse off".