Iranian Revolutionary Guards boards the UK-flagged tanker Stena Impero, Strait of Hormuz, July 19, 2019

The UK is planning its response to Friday’s seizure of a British oil tanker by Iran’s Revolutionary Guards, reportedly considering new sanctions against Tehran.

The Government has drawn up measures for asset freezes on Iranian officials and will press for European Union and UN punishment, according to The Telegraph. Foreign Secretary Jeremy Hunt is expected to use a statement in Parliament’s House of Commons to announce the steps.

The EU and UN lifted their sanctions in 2016 during implementation of the nuclear deal between Iran and the 5+1 Powers (US, Britain, France, Germany, Russia, and China).

Germany, France and other European countries have expressed their concern about Iran’s action; however, Russia and China are likely to oppose any re-imposition of the UN Security Council’s sanctions.

After a Saturday meeting of the COBRA emergency committee, Hunt repeated that the seizure of the Stena Impero raised “very serious questions” about security the Strait of Hormuz, through which 1/6th of the world’s oil passes.

UK officials said the tanker, which was en route to Saudi Arabia to load oil, was in Oman’s territorial waters when it was intercepted and taken to the port of Bandar Abbas in southern Iran.

The Iranian chargé d’affaires, Mohsen Omidzamani, was summoned to the Foreign Office. UK officials spoke of unspecified measures to step up protection of shipping through the Strait.

Defence Secretary Penny Mordaunt said the Royal Navy frigate HMS Montrose was an hour away when the Steno Impero was boarded in a “hostile act”.

Last week, HMS Montrose intervened when Revolutionary Guards speedboats approached another tanker, BP’s British Heritage.

Iran Daily, July 11: Tehran’s Forces Fail to Intercept UK Oil Tanker — Officials

Retaliation or “Maritime Violation”?

Iranian military commanders and officials had vowed retaliation for the UK’s seizure of an Iranian supertanker in Gibraltar’s waters on July 4.

On Monday, the Supreme Leader promised:

The vicious British government committed piracy and attacked our ship; they commit crimes and legalize it. The Islamic Republic and the believing members of the establishment will not leave such vicious acts without a response.

Iran Daily, July 16: Supreme Leader Threatens Retaliation v. UK “Piracy”

The Grace 1, carrying 2.1 million barrels of oil, was intercepted at the mouth of the Mediterranean, having taken the long route around the southern tip of Africa. The UK said the supertanker was breaking European Union sanctions on oil deliveries to Syria’s Assad regime. The Revolutionary Guards denied the vessel was en route to the port of Baniyas in western Syria.

Iran’s official line is now that the Stena Impero violated maritime regulations and collided with a fishing boat.

Allah-Morad Afifipoor, the head of the Ports and Maritime Organization in southern Hormozgan Province, said on Sunday that the tanker had not responded after the accident and had its changed route. He maintained that the Revolutionary Guards had “guided” the vessel to Bandar Abbas so an investigation could be conducted.

Asked how long this would last, he said it depended on the cooperation of the vessel’s 23 Indian, Russian, Philippine, and Latvian crew and authorities’ access to documents.

But the hardline Kayhan newspaper, linked to the Supreme Leader’s office, pushed aside the official story:

And Foreign Minister Mohammad Javad Zarif alluded to the UK impoundment of the Grace 1 as he held to the official explanation: