Foreign Secretary Jeremy Hunt said:
"I had a fairly long conversation with the Iranian Foreign Minister, Javad Zarif, this afternoon. And it’s clear from talking to him and also statements made by Iran that they see this as a tit-for-tat situation, following Grace 1 being detained in Gibraltar. Nothing could be further from the truth. Grace 1 was detained legally in Gibraltarian waters because it was carrying oil against EU sanctions, to Syria, and that’s why Gibraltarian authorities acted totally with respect to due process and totally within the law.
"The Stena Impero was seized in Omani waters in clear contravention of international law. It was then forced to sail into Iran. This is totally and utterly unacceptable.
"It raises very serious questions about the security of British shipping and indeed international shipping in the Straits of Hormuz. And so, we spent a long time this afternoon in COBR discussing how we can guarantee the security of British and international shipping. A statement will be made to Parliament on Monday to update the House of Commons and the country on the measures that we are going to take, the further measures. But already this weekend we have raised the threat level to level 3 – that was a decision made by the Transport Secretary. But we will take further measures and announce those measures going forward on Monday.
"Our priority continues to be to find a way to de-escalate the situation. That’s why I reached out to the Iranian Foreign Minister, that’s why due process in Gibraltar continues. But, we need to see due process happening in Iran as well. We need to see the illegal seizing of a British-flagged vessel reversed, we need that ship released, and we continue to be very concerned about the safety and welfare of the 23 crew members."