BRITAIN is to seek to put together a European-led maritime mission to protect ships sailing through the Strait of Hormuz following the seizure by Iran of a British-flagged tanker.

Following a meeting of the Government’s Cobra emergencies committee, Foreign Secretary Jeremy Hunt said “constructive discussions” had taken place with a number of countries over the preceding 48 hours.

In a Commons statement, Mr Hunt condemned the detention of the Stena Impero by Iranian Revolutionary Guards on Friday as an “act of state piracy”.

He said the proposed new European mission would focus on ensuring free navigation through one of the world’s most important waterways, which carries a fifth of the world’s oil and a quarter of its liquefied natural gas flow.

It would seek to “complement” US proposals to protect shipping in the region, although it would not form part of the American “maximum pressure” policy on Tehran as the UK continued to support the Iran nuclear programme.

“It is with a heavy heart that we are announcing this increased international presence in the Gulf, because the focus of our diplomacy has been on de-escalating tensions in the hope that such changes would not be necessary,” Mr Hunt said.

He added: “If Iran continues on this dangerous path, they must accept the price will be a larger Western military presence in the waters along their coastline, not because we wish to increase tensions but simply because freedom of navigation is a principle which Britain and its allies will always defend.”

Mr Hunt confirmed the Department for Transport had raised the security level for British-flagged shipping to its highest level - level 3 - and was advising against passage through Iranian waters.

It was also urging those ships which were planning to sail through the Strait of Hormuz to notify the UK authorities so they could if necessary arrange for them to travel in convoy.

Mr Hunt confirmed the Royal Navy Type 23 frigate HMS Montrose had tried to reach the Stena Impero after it radioed for help but was unable to reach it in time.