Britain’s airports and nuclear power stations have been told to tighten their defences against terrorist attacks in the face of increased threats to electronic security systems.

Security services have issued a series of alerts in the past 24 hours, warning that terrorists may have developed ways of bypassing safety checks.

Intelligence agencies believe that Islamic State of Iraq and the Levant (Isil) and other terrorist groups have developed ways to plant explosives in laptops and mobile phones that can evade airport security screening methods.

It is this intelligence which is understood in the past fortnight to have led the US and Britain to ban travellers from a number of countries carrying laptops and large electronic devices on board.