US-Israeli intelligence believe the drone was launched from ­eastern Yemen and directed by GPS towards the tanker before an operator took control for the final mile, directing the rocket via camera into the ship’s bridge.

The attack happened on July 30, some 152 nautical miles north-east of the Omani port of Duqm.

British special forces were in Yemen last night to hunt down terrorists behind the drone attack which killed a British security guard on a tanker in the Gulf.

It is believed that Iranian-backed Houthi rebels carried out the ­atrocity at the behest of Tehran. 

General Sir Nick Carter, head of Britain’s Armed Forces, has called for Western retaliation for the attack which killed Adrian Underwood, a former British ­soldier working for UK firm Ambrey to provide ­security for the vessel, and its Romanian captain. He said: “What we need to be doing is calling out Iran for its very reckless behaviour.”

A 40-strong team of SAS ­soldiers arrived in eastern Yemen yesterday.

Landing at Al Ghaydah ­airport in Mahra, they are said to be using local handlers, ­subsidised by the Foreign Office, who have know­ledge of the region to help hunt the Houthi mercenaries responsible. The team also includes a specialist ­electronic ­warfare unit which can deploy resources to hoover up communications chatter.

It is feared Tehran supplied the militants with the long-range unmanned aerial vehicle (UAV), to threaten international ­merchant vessels in some of the world’s ­busiest shipping lanes.

The SAS team is operating with a US special operations force which was already in the region and helping to train an elite Saudi commando unit. The UK, US and Israel have condemned Iran for the attack on MV Mercer Street, though the Islamic regime denies involvement. Operated by London-based Zodiac Maritime, part of Israeli ­billionaire Eyal Ofer’s Zodiac Group, the vessel was heading from Tanzania to United Arab Emirates.

The UK mission will send a clear message to Iran that the UK will not tolerate such attacks in international waters.

And Israeli Foreign Minister Yair Lapid, who said he was in constant contact with British counterpart Dominic Raab, said he “noted to him the need to respond severely”.

A senior UK military source said last night: “Everything points to the drone being launched from Yemen. The concern now is that an extended range drone will give them a new capability.”

Ebrahim Raisi, dubbed the “butcher of Tehran” for his role in the massacre of 30,000 political prisoners in 1988, was sworn in as the Islamic regime’s eighth president on Thursday.

Daily Express