British warship was an hour from tanker seized by Iran in 'hostile act'

• Alan Mendoza: The only surprise about Iran's seizure is that it didn't happen sooner

• Analysis: Boris Johnson could face early test as Iran 'exploits' political uncertainty

• US developing 'coalition' of navies to protect ships amid Iran tensions

• Mark Almond: Brexit myopia and a fatal lack of foresight has enabled Iran to put Britain on the spot

• Former head of Navy questions why British ships weren't protected amid threats

• Foreign office summon Iranian diplomats ahead of emergency Cobra meeting 

Britain has admitted its nearest warship was one hour away from the merchant vessel seized by Iran in the Strait of Hormuz on Friday and could do nothing to help.

Penny Mordaunt, the defence secretary, said the incident happened in Omani waters and was a "hostile act".

But she said the British Type 23 frigate HMS Montrose was 60 minutes away from being able to help the Stena Impero when it was boarded by Iranian Revolutionary Guards.

The Foreign Office summoned Iran's charge d'affaires, Mohsen Omidzamani, following the seizure of the British-flagged oil tanker.

It came as Jeremy Hunt spoke to his Iranian counterpart Mohammad Javad Zarif  to express Britain's concern over the latest hike in tensions in the region.

Mr Hunt wrote on Twitter: "Just spoke to Iranian FM Zarif  and expressed extreme disappointment that having assured me last Saturday Iran wanted to de-escalate situation they have behaved in the opposite way.

"This has to be about actions not words if we are to find a way through. British shipping must and will be protected."

Mr Zarif hit back with his own tween, stating: "Unlike the piracy in the Strait of Gibraltar, our action in the Persian Gulf is to uphold int'l maritime rules. As I said in NY, it is IRAN that guarantees the security of the Persian Gulf & the Strait of Hormuz. UK must cease being an accessory to #EconomicTerrorism of the US."

Following a meeting of the Government's emergency committee Cobra, a spokesman said the seizure was "a clear challenge to international freedom of navigation", adding: "As the Foreign Secretary has said, our response will be considered and robust and there will be serious consequences if the situation is not resolved."

Iran has directly linked the seizure of the tanker with Britain's role in detaining a tanker carrying Iranian oil earlier this month.

A spokesman for Iran's Guardian Council was quoted as saying "the rule of reciprocal action is well-known in international law" and that Tehran made the right decision in the face of an "illegitimate economic war and seizure of oil tankers".

The explanation, contrasts with Iran's earlier claims that the Stena Impero collided with a fishing vessel in the Persian Gulf, as tensions mount in the strategic waterway, a chokepoint for around a third of the world's sea-borne oil.

Allahmorad Afifipour, the head of Ports and Maritime Organisation in southern Hormozgan province claimed the Swedish-owned Stena Impero was in an accident with an Iranian fishing boat whose distress call it ignored.

The 30,000-tonne ship had been en route to Saudi Arabia, but abruptly changed course and began sailing towards the Iranian island of Qeshm, data relayed by maritime tracking services showed. It then “went dark”, meaning its transponder was turned off, at 4.29pm UK time and nothing has been heard from her or her 23 crew since.

The tanker's operator, Stena Bulk, said on Friday the ship had been "in full compliance with all navigation and international regulations", but was no longer under the crew's control and could not be contacted.

Guards say it was taken to Bander Abbas port, where its Russian, Ukrainian, Indian, Latvian and Filipino crew are being questioned.

Mr Hunt said this morning that he was worried that Iran had taken a "dangerous path".

"Yesterday's action in Gulf shows worrying signs Iran may be choosing a dangerous path of illegal and destabilising behaviour after Gibraltar’s LEGAL detention of oil bound for Syria," Mr Hunt said on Twitter.

"Our reaction will be considered but robust. We have been trying to find a way to resolve Grace1 issue but WILL ensure the safety of our shipping."

A Whitehall source told the Telegraph: “It looks as though the Iranian Revolutionary Guard have boarded and taken a UK-flagged ship. It appears to be linked to events around the Grace 1 tanker.”

British authorities seized the Iranian Grace 1 supertanker off the coast of Gibraltar on July 4, on suspicion it was carrying crude to Syria in violation of European Union sanctions.

The fate of the tanker has been at the centre of escalating tensions between the UK and Iran and was seen as a pawn in the standoff between the Islamic Republic and the West.

Why was the ship not protected in face of Iran threat?

The former head of the Royal Navy on Saturday questioned why British shipping has been allowed to go through the Straits of Hormuz without military protection.

Lord West, the former 1st Sea Lord, said it was “foolhardy” and “unacceptable”, for UK shipping to transit the area without a Royal Navy escort in the face of threats by the Iranians to seize ships.

However, he also acknowledged that any ban on British shipping travelling through the Straits of Hormuz without an escort would be difficult to enforce, because the Navy would have “too few” ships to escort them all.

An escort-only policy would effectively mean fewer British merchant vessels sailing through the Straits, with a knock-on effect on trade in an area through which a third of the world's sea-borne oil is transported.

Reacting to the seizure of the British-flagged vessel the Stena Impero by Iran’s Revolutionary Guards on Friday, Lord West said: “What I find extraordinary is that we knew that the Iranians would try something like this a few days ago. This is hardly a surprise. The Iranians said very clearly they intended to do this and they have done it.”

He told Sky News: “I’m absolutely amazed that we haven’t implemented some sort of control of red ensign shipping within the region whereby no tanker would go in to what is clearly a dangerous zone without an escort, and I find it bizarre that we seem to have ships doing exactly that.”

But Lord West admitted the British navy had “too few ships” and would find it “extremely difficult” to provide such escorts to merchant vessels.

Between 15 and 30 British-flagged tankers pass through the strait every day, with only seven Royal Navy vessels, accompanied by Royal Marines, for force protection in the Gulf.

The UK had sent an extra navy ship to protect British-flagged oil tankers travelling through the Gulf last weekend after “specific” threats from the Islamic Revolutionary Guards Corps.

HMS Montrose, a Type 23 frigate, was already in the area. HMS Duncan - Britain’s most advanced warship - was also sent.

HMS Montrose was dispatched on Friday to go help the Stena, but arrived minutes too late when it was already in Iranian waters.

British ministers are now expected to face difficult questions about the decision to seize the Iranian Grace 1 supertanker off Gibraltar on July 4, without ensuring that it could protect British-owned shipping in the Straits of Hormuz.

Critics have already questioned whether the UK confronted Iran knowing that the Gulf waterways were not adequately policed.

Chris Parry, a former Royal Navy warfare officer and aviator, who now runs a strategic forecasting company, said: “Why are ship owners dumb enough to sail their ships independently through a threat area?  Convoys are needed as in the 1980s to counter a weak Iranian regime that has lost control of the organised crime bosses of the Iranian Revolutionary Guard.

“UK government should declare an exclusion zone around all British flagged ships.  If you are gangsters from Iranian Revolutionary Guard, enter at your peril.”

Shortly before the Stena Impero was seized the MoD had released a statement the state of the Royal Navy presence in the area.

It stated last Tuesday: “Since 1980, units of both the Royal Navy (RN) and the Royal Fleet Auxiliary (RFA) have maintained a presence in the Gulf 24 hours a day, seven days a week, 365 days a year.

“We have approximately 1,200 UK personnel deployed and are committed to de-escalation in the Gulf and maintaining free navigation through the region.”

It added: “The UK regularly reviews the number of RN and RFA vessels in the region.”