London's stock exchange index, the FTSE, unveiled a new index to guide American investors away from investing in some 400 major companies doing business with the 'outlaw' states of Iran, Sudan, Syria and North Korea.

The new terror-free index, created in partnership with a Washington, DC-based outfit tracking terror financing, follows the change in US law that requires managed funds to dump investments in companies doing business in the four rogue nations.

Technically investors which continue to invest in any of these 400 companies could now risk falling foul of the law.