Video report by ITV News Correspondent Lucy Watson
Royal Marines were involved in a "brave" and "bold" operation to seize an Iranian supertanker thought to be carrying oil heading to Bashar al-Assad's Syria.
The marines worked alongside authorities in Gibraltar to detain the 1,082-foot oil tanker, thought to be heading to the Banyas refinery in Syria, which would have breached European Union sanctions.
Foreign Secretary and prime ministerial hopeful Jeremy Hunt praised the swift actions that denied Assad's "murderous regime" of oil.
However there are now fears an international diplomatic row has been stoked.
The seizure of the tanker comes at a time of growing tension between the US and Iran.
The agreement aimed at halting Tehran’s nuclear programme is unraveling and Iran has been accused of sabotaging oil tankers in the strait of Hormuz. Experts say it was designed to show Donald Trump there are consequences over his decision to pull out of the nuclear deal and impose economic sanctions.
The video below has no sound
Video footage below shows the Iranian tanker just off the coast of Gibraltar early this morning.
The Royal Marines were drafted in for their specialist boarding skills to ensure the Royal Gibraltar Police could get onto the tanker at sea.
No shots were fired by the Royal Marines from the 42 Commando during the operation.
The first marines descended onto the tanker from a Wildcat helicopter, while others used rigid inflatable boats.
Around 16 Royal Gibraltar Police officers were also involved in the mission.
Gibraltar’s chief minister Fabian Picardo praised those involved in the mission.
Mr Picardo said: “We have detained the vessel and its cargo. This action arose from information giving the Gibraltar government reasonable grounds to believe that the vessel, the Grace 1, was acting in breach of EU sanctions against Syria.
“In fact we have reason to believe that the Grace 1 was carrying its shipment of crude oil to the Banyas refinery in Syria.”
The tanker was flying a Panama flag and was seized on Thursday morning.
Downing Street welcomed the operation and said it sent a clear signal about the sanctions regime.
The Prime Minister’s official spokesman said: “We welcome this firm action to enforce EU sanctions against the Syrian regime and commend those Gibraltarian authorities involved in successfully carrying out this morning’s operation.
“This sends a clear message that violation of the sanctions is unacceptable.”
The EU has imposed a series of sanctions against Assad’s regime in Syria in response to the conflict in the country.
Some 270 individuals and 69 entities are listed in the sanctions regime.