Allen & Overy (A&O) has emerged as the lead adviser to the arranging banks on the highly controversial $492m (£346m) bond issue by Iran – the first foreign bond to be issued by the country since the Islamic revolution of 1979.

The issue has split fund managers at the world’s top investment banks following US President George Bush’s statement that Iran was part of an “axis of evil” that supports terrorists in light of the 11 September attacks on New York.