Royal Marines seized the Panamanian flagged vessel by Gibraltar on suspicion it was heading to Syria, in defiance of against EU sanctions, following a US request. Britain’s ambassador in Tehran assured the Iranian regime the move was against Damascus and that Britain views Iran’s oil trade as legitimate in general. Mr Hunt tweeted: “Just spoke to Iranian Foreign Minister Zarif. Constructive call. I reassured him our concern was destination not origin of the oil on Grace One & that UK would facilitate release if we received guarantees that it would not be going to Syria, following due process in Gibraltar courts.
The Lebanese political party and militant group, Hezbollah, considered a terrorist organisation by London and widely accepted as a Tehran proxy is also fighting in Syria alongside pro-Assad forces.
Grace I for the time being remains in detention.
The captain and chief officer were arrested by Gibraltarian officials but released on bail without charge.
Iran’s oil supply is considered to be vital to the survival of their economy.
Increasing sanctions by the Donald Trump administration has caused a sharp decrease in the level of exports.
The British Government has long sought to ease tensions with the regime.
London has joined Paris and Berlin in a desperate attempt to save the Iran nuclear deal.
Mr Trump pulled out of the agreement last year increasing tensions in the region.