Marsh & McLennan directors may force chief executive Jeffrey Greenberg to step down after the world’s largest insurance brokerage lost two-fifths of its market value following a lawsuit by New York Attorney General Eliot Spitzer, investors said.

At least 170 British investors were allegedly duped out of £30m (€45.6m) by US fraudsters who convinced them they were helping to fight the war on terror, it emerged today.