A newly-released recording has revealed the tense exchange between the Royal Navy and Iranian military in the run-up to the seizure of a British oil tanker.
In the clip recorded during Friday's incident an Iranian vessel can be heard repeatedly warning the British-flagged Stena Impero to change course, saying: "If you obey you will be safe."
HMS Montrose can then be heard telling the tanker: "As you are conducting transit passage in a recognised international strait, under international law your passage must not be impaired, impeded, obstructed or hampered."
It then informs Iran any attempt to board the Impero would be a "violation of international law", during the three-minute clip obtained by maritime security firm Dryad Global.
Speed boats would later surround the vessel and balaclava-clad Iranian troops abseil on to its deck, with footage of the dramatic scenes released by Iran's Fars news agency yesterday.
It has since been reported the Impero may have been sent spoof coordinates by Russian spy technology.
The Iranian Revolutionary Guard seized the Impero in the Strait of Hormuz, a key shipping route in the Gulf, claiming it was "violating international maritime rules".
HMS Montrose raced to assist the Impero but was too late.
Foreign Secretary and Tory leadership hopeful Jeremy Hunt has rubbished Iran's claims the vessel was in the wrong, saying Iran's actions were a "clear contravention of international law".
Stena Bulk, which owns the tanker, said it had been in international waters at the time of the seizure.
The Impero's crew, who are Filipino, Russian, Latvian and Indian, are said to be in good health.
Mr Hunt says Iran views the seizure as a legitimate response to the Royal Marines helping capture an Iranian tanker off Gibraltar earlier this month.
It was believed the Grace 1 was carrying oil to Syria in contravention of EU sanctions but Iran denied that and described the seizure as an act of "piracy".
Defence Minister Tobias Ellwood this morning denied the UK had taken its "eye off the ball" and said the government was looking at a "series of options".
Asked during his appearance on Sky's Sophy Ridge on Sunday whether the UK had taken its "eye off the ball", he replied: "No, not at all."
Mr Ellwood said the UK had vessels going through 100 nautical miles of waterway every day, adding: "It is impossible simply to escort each individual vessel."
Asked if sanctions were off the table, Mr Ellwood said: "Cobra was taking place yesterday, so we're looking at the operational responsibilities from that but, yes, we are going to be looking at a series of options."
The full exchange:
Iran: "If you obey you will be safe, if you obey you will be safe. Alter your course to 360 degrees immediately."
HMS Montrose: "Stena Impero, this is British warship Foxtrot 236 I reiterate that as you are conducting transit passage in a recognised international strait, under international law your passage must not be impaired, impeded, obstructed or hampered. Please confirm that you are conducting transit passage in a recognised international srait."
IR: "Stena Impero, I say again, you are ordered to change your course 360 degrees immediately. If you obey you will be safe."
HMS: Inaudible.
IR: "No challenge is intended, no challenge is intended. I want to inspect the ship for security reasons."
HMS: "Sir, the requests you are transmitting to the Stena Impero hinder and impair her passage. You must not impair, impede, obstruct or hamper the passage of the Stena Impero. Please confirm you are not intending to violate international law by unlawfully attempting to board the Stena Impero."
IR: "If you obey you will be safe, if you obey you will be safe. Alter your course 360 degrees immediately."
