Foreign Minister Mohammad Javad Zarif left Tehran for London to visit the UK, IRNA reported.
Zarif, heading a high-ranking delegation, departed to London an hour ago to discuss bilateral ties and regional developments with senior British officials.
Zarif will be the first Iranian foreign minister to visit Britain in 12 years.
Former Iranian Foreign Minister Kamal Kharrazi was the last to visit London in 2004.
On August 23, British Foreign Secretary Philip Hammond reopened Britain's embassy in Iran after four years of strained relations between Tehran and London.
Hammond arrived in Tehran in late August at the head of a high-ranking delegation to meet the Iranian officials and reopen the British embassy.
Upon arrival, he directly went to the British embassy and announced resumption of the mission's operation in an official ceremony.