Britain has secretly deployed its most advanced warship off the coast of Yemen to guard a crucial shipping lane from Iranian-backed missile attacks threat, according to The Times.

The warship has been sent to protect the Bab al-Mandeb route following attacks on three U.S. warships and a United Arab Emirates vessel there.

The vast majority of Britain’s oil and gas supplies take this route as their main passage which leads to the Suez Canal; any obstacle would mean the electricity could be cut off across Britain, said Peter Roberts, a senior research fellow at the Royal United Services Institute, who stressed the importance of keeping the strait open.

The threat of attacks against vessels using the shipping lane is an expansion from the conflict in Yemen where Iran-backed Houthi rebels are attacking Yemeni government forces; supported by a Saudi-led coalition and armed with British weapons.

A suspected Houthi missile strike destroyed the UAE vessel that was providing support to the coalition at the start of last month in an attack that was filmed and posted on YouTube. There were three subsequent suspected Houthi missile launches over the next fortnight against the warships USS Mason, USS Nitze and USS Ponce; none hit their targets.

“This is about Iranians and their proxy war against the Saudis,” said Gerry Northwood, chief operating officer of MAST, a British maritime security firm.

Britain has abstained from announcing the deployment of Daring off Yemen because of the sensitivity of such a powerful UK warship appearing to be linked to the conflict, stated The Times.

“The destroyer, which can shoot down missiles, had been heading to the Gulf with HMS Ocean, the UK’s flagship which is due to take charge of coalition naval operations against ISIS later this month.”