UK and US announce joint security mission to protect ships as Iran tensions rise

Britain is to join a new US-led maritime security mission to protect international shipping in the Gulf - but without the support of EU allies.

The Ministry of Defence has said that the Royal Navy would be working with the United States Navy to assure the security of merchant shipping passing through the Strait of Hormuz.

The move follows the seizure last month by Iranian Republican Guards of the British-flagged tanker Stena Impero.

The MoD said the mission would largely draw on assets already in the region including the warships HMS Duncan and HMS Montrose.

The UK has also offered to lead one of the mission's maritime task groups.

Defence Secretary Ben Wallace said: "The UK is determined to ensure her shipping is protected from unlawful threats and for that reason we have joined the new maritime security mission in the Gulf.

Defence Secretary Ben Wallace made the announcement (Getty)

"The deployment of the Royal Navy assets is a sign of our commitment to our UK-flagged vessels and we look forward to working alongside the US and others to find an international solution to the problems in the Strait of Hormuz."

Britain currently has deployed a destroyer HMS Duncan and a frigate HMS Montrose to the Gulf to accompany UK-flagged vessels through the strait.

So far, 47 ships have been accompanied by the naval vessels, British officials said.

Earlier on Monday, Iran's Foreign Minister Mohammad Javad Zarif said Tehran would no longer tolerate "maritime offences" in the strait.

It has threatened to block all exports via the Strait, through which a fifth of global oil traffic passes, if other countries comply with U.S. pressure to stop buying Iranian oil.

British foreign minister Dominic Raab said the latest move did not represent a change in approach to Iran and Britain remained committed to maintaining the 2015 nuclear deal agreed with Tehran in return for an easing of sanctions.