Iran and the UK have been cooperating in Rhum gas field in North Sea since December 2005, when the field started pumping, until the imposition of the US-engineered sanctions against Iran.
It led to a stoppage of gas production from the field in 2010.
Rhum gas field, which cost $565 million to develop, is shared equally by BP and the Iranian Oil Company, a subsidiary of the state-owned National Iranian Oil Company.