Men who safeguard their nations' ultimate weapons on both sides of the Atlantic shared their expertise during a fortnight of joint training in the UK.
R Squadron, 43 Commando Fleet Protection Group Royal Marines, make sure Britain's nuclear deterrent is safe - be it the Vanguard-class submarines which carry the Trident missiles when alongside in Faslane, or the weapons' storage facility at Coulport.
And 4,000 miles away in Kings Bay, Georgia, or 4,500 miles away in Bangor, Washington, the US Marine Corps Security Force Regiment does exactly the same looking after its deterrent.
The near-identical missions has led to a long-standing bond of friendship between the two marine units, a friendship which is strengthened each year by combined training on both sides of the Pond, Exercise Tartan Eagle.
The two-week-long British leg is spread far and wide, reaching far beyond the confines of Faslane.
Week one is held in the field: the Brits and Americans conduct navigation and survival training at Garelochead, culminating in all ranks completing the original speed march - a seven-mile slog from Spean Bridge, where the Americans learned about the history of the Corps and the birth of the commandos in the 1940s; some 25,000 forerunners of today's green berets passed through the training centre at nearby Achnacarry during WW2.
43 Commando's American guests were then brought bang up to date with a week on Northumbria Police' indoor/outdoor range at Follingsby Park in Gateshead.
The business park is home to the usual cash and carries, parcel depots and warehouses, plus Mister Twisters children's indoor playground and Northumbria Police Operational and Tactical Training Centre.
Indoors it features two 60-metre firing ranges (plenty big enough to drive vehicles around in if you so wish), a 'judgmental suite' - a CGI simulator at which the shooter and the target can react to each other's movements.
And outdoors, there's a 'tactical training area' - a mock-up of a street with blocks of flats and terraced houses which you can smash your way into and fight your way through..
When they go to Virginia in October, 43 Commando will experience something similar when they're invited to use the US Marines' 'shoot house' for live firing training.
'Tartan Eagle has offered a fantastic opportunity for both the Royal Marines from R Squadron and their American counterparts to train together and share tactics and best practice that can be employed on operations," said Capt Glen Moxham, R Squadron's Second in Command, who organised the UK phase of the exercise.
