Britain's Royal Air Force scrambled spy planes as it joined NATO in a huge hunt for a Russian submarine suspected of threatening a US aircraft carrier off Norway.
In what defence sources are calling a 'highly unusual surge' of activity, NATO allies have deployed at least 27 specialist submarine-hunting sorties since Sunday in an urgent bid to track the vessel.
The operation, which insiders insist is not a drill, comes as the USS Gerald R. Ford - the most advanced and expensive aircraft carrier in the world, worth around £11 billion, carries out exercises with the Norwegian Navy in Arctic waters.
The Royal Air Force has dispatched eight P-8A Poseidon aircraft from RAF Lossiemouth in Scotland, while the Norwegian Air Force launched three more flights from Evenes Air Base near Narvik, deep inside the Arctic Circle.
The US Navy has also scrambled patrol planes from a base in Iceland and flown in reinforcements from Sicily to bolster the search effort, according to The Sun.
