Rich countries risk stoking protectionism by blocking foreign takeovers on grounds other than national security, a senior White House official has warned.

Dan Price, the international economics official at the White House National Security Council, said the Group of Eight rich countries must “lead by example”. Mr Price, one of the key officials preparing for the July G8 summit in Japan, told the Financial Times that the group should issue “a strong . . . statement on open investment and trade policies”. This should be “aimed not only outward but to the G8 countries themselves”.