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

British Ministers “failed” in allowing merchant ships to continue sailing through the Gulf when the nearest Royal Navy escort was an hour away, former defence chiefs said yesterday.

Lord Dannatt, former Chief of the General Staff, said it was surprising measures had not been taken to protect British shipping in the face of threats by the Iranians to retaliate over the impounding of one of their ships in Gibraltar.

Following the seizure of the British-flagged vessel the Stena Impero by Iran’s Revolutionary Guards on Friday, British ministers are facing difficult questions about the decision to seize the Iranian Grace 1 supertanker off Gibraltar on July 4, without ensuring that it could first protect British-owned shipping in the Straits of Hormuz.

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

But it has now emerged that HMS Montrose, a Type 23 frigate dispatched on Friday to help the Stena, was an hour away from reaching the tanker - by which time the Stena had already been diverted into Iranian waters by Islamic Revolutionary Guards.

Lord Dannatt told The Telegraph: “It would have been prudent to marshall out resources in the area to prevent our shipping being seized. We failed.

“It was known that the Iranian would try to seize a British ship and it would have been wise to ensure none of our ships were in danger. It’s perfectly possible to come up with an escort for ships through the Straits.”

His words were echoed by Lord West, the former 1st Sea Lord, who said it had been “foolhardy” and “unacceptable”, for UK shipping to transit the area without a Royal Navy escort.

“We have to run convoys of merchant ships with a Navy escort so we can look after them. It was very stupid of us to allow a merchant ship to go through those waters before HMS Montrose was close enough to look after her,” said Lord West.

“As soon as we seized Grace 1 we should have been aware the Iranians would retaliate. We should have instituted protection measures for the control of merchant shipping and said to the Stena Impero to wait in port until we could escort you through the Stratis with one or two warships.”

Both Lord West and Lord Dannatt argue that while in the long term Britain needs more ships as part of a bigger defence budget, it has the capability to protect merchant ships sailing through the Gulf if they coordinate their movements with the Royal Navy.

They also urged ministers to make efforts to assemble a coalition of allies to provide protection for merchant vessels in the Gulf, something that already appears to have been rejected in Whitehall.

“It needs an international response to look after merchant shipping,” said Lord West.

Their warnings came as senior MPs and Peers said the new prime minister will need to boost defence spending if Britain wants to remain a significant global player.

The Joint Committee on the National Security Strategy will warn today that the Global Britain agenda championed by Theresa May's Government was "meaningless" against a backdrop of "reduced diplomatic spending and under-powered defence".

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.

Critics have already questioned whether the UK confronted Iran by seizing the Grace 1 knowing that the Gulf waterways were not adequately policed.

Chris Parry, a former Royal Navy officer, who now runs a strategic forecasting company, wrote on Twitter: “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.”

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

It said: “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.”