Special forces divers have been searching for terrorist mines attached to gas tankers that come into UK ports, it has emerged.
It is understood that frogmen from the Special Boat Service (SBS) and specialists from the Royal Navy have been carrying out covert searches of the vessels.
It is feared that Islamist terrorists have attached explosive devices to ships while they are in the Middle East, in order to detonate them when they reach the UK.
The tankers unload at terminals in the Isle of Grain in Kent and at Milford Haven in Wales, before the gas is fed to power stations.
A senior Naval source said there was even the possibility that terrorists could plant mines on ships once they have entered UK waters.
They said: “The threat against gas tankers emerged a couple years ago and we have been training to counter it ever since. The concern is that tankers could be sailed into UK waters and destroyed either with mines or improvised explosive devices [IEDs].
“It is entirely possible a major incident could result in fuel shortages in the UK and this would be disastrous economically.”
The operation is believed to have started two-years-ago after intelligence emerged that terrorists had either acquired limpet mines, which can be attached to a ship’s hull, or were planning to develop a similar device.
Navy divers involved in “underwater force protection operations” – searching ships for mines – come from the SBS and from an elite team called Fleet Diving Unit 1.