Royal Marines have forced US troops to surrender just days into a training exercise after eliminating almost the entire unit.
The British commandos “dominated” US forces during a training exercise in California, using a new battle structure.
The Telegraph understands the US forces asked for a “reset” half way into the five-day war fighting exercise, having suffered significant simulated casualties.
At one point in the battle, the commandos’ “kill board”, an intelligence assessment of the level of damage inflicted upon enemy equipment and units, had a tick against almost every American asset, indicating it had been deemed destroyed or rendered inoperable.
Lieutenant Colonel Andy Dow, commander of the British force, said: “Throughout this deployment our focus has been on integrating game-changing capabilities from across the commando force to deliver disproportionate effect in the face of a free-thinking peer adversary.”
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The British troops used the exercise to trial the new Littoral Response Group (LRG) structure, around which the future commando force will be built.
Under reforms directed by the First Sea Lord, Admiral Sir Tony Radakin, Britain’s commando forces are to become more flexible and mobile fighting troops.
Following the restructure of amphibious forces, Britain will have two LRGs each based around an existing unit of Royal Marines.
Nato’s northern and Baltic flanks will be covered by LRG (North), based in the UK. The second - LRG (South) - will be based afloat in and around the Omani port of Duqm, focussing on British military activity in the Indo-Pacific region.
LRG (South), built around Taunton-based 40 Commando, will be held at a high state of readiness from next year. Each LRG will be able to work with the carrier strike group to produce an expeditionary strike force capable of operating anywhere in the world for extended periods of time.
Exercise Green Dagger is attended by military forces from multiple countries and takes place in one of the biggest military training areas in the world. The exercise is designed to test US Marine Corps units prior to them being deployed overseas.
The exercise area covers over 3500 square kilometres of mountainous and desert terrain, and includes urban settings with actors playing civilians who can choose to help or hinder the military forces and do not have to follow a script.
The weeks leading up to the main exercise saw LRG (South) train with troops from the US, Netherlands, Canada and UAE.
The Royal Marines' success was achieved by targeting the US headquarters and valuable equipment, paralysing counter-attacks from the Americans.
British artillery also focused on destroying enemy vehicles and artillery positions.
The US were eventually defeated by a British long-range commando assault supported by fighter jets.
The exercise concluded with a last minute US assault which was repelled, leaving the Royal Marines in control of over 65 per cent of the entire area, having started with less than 20 per cent.
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