The comments came as Hammond visited Iran to reopen the British embassy in Tehran. The Iranian embassy in London has also been reopened, as diplomatic ties grow between the countries after the British embassy was stormed in 2011 by protesters in retaliation against economic sanctions.
Diplomatic ties are being re-established following the Iran nuclear deal that was reached last month. The US, UK, France, China, Russia and Germany - the so-called P5+1 - agreed to lift sanctions in return for allowing UN nuclear inspectors extensive, but not automatic, access to sites within Iran.
Bosses from Britain's largest business groups and energy companies broke new ground over the weekend by travelling with Hammond to Iran, hoping to make future trade deals.