Lobbing shells, firing rifles, sending patrol craft tearing up rivers and putting tanks ashore to roam around at will in the United States is not normally to be advised.

It sounds a sure-fire way to upset the Pentagon – but all was well as the combatants were invited.

The core of the RN Fleet and Royal Marines assembled in and off the eastern seaboard of the United States for the largest deployment of Naval forces since conflict in Iraq.

Exercise Aurora reached its peak in mid-June as sailors, soldiers and airmen from nearly a dozen nations did battle.

At the climax of the ‘war’, codenamed Exercise Rapid Alliance, 30,000 men and women – 6,000 of them British – were fighting in a massive test of the amphibious capability of the Allied nations.

It has also been the first acid test for the Royal Navy’s enhanced amphibious forces, with new assault ship HMS Albion deployed for the first time since she was declared ready for front-line duties.

She and helicopter carrier HMS Ocean served as the launch-pad for the main assault as troops were ferried ashore by landing craft, Sea King Mark IVs and Chinooks.

Live firing exercises allowed troops to loose a few rounds on land with SA80 rifles and field artillery, while HMS Cornwall let rip with her 4.5in main gun in firing exercises off shore.

Her crew also took part in rapid-roping from her Sea King helicopter to ward off ‘suspicious’ boats threatening the landings.

Sea Harriers and RAF GR7 variants of the jump jet based on HMS Invincible provided air cover.

Lt Col Buster Howes, Commanding Officer of 42 Commando, said the exercises had done “a great deal to foster further relations between our corps and the US Marines”.

He added: “The realistic training my men underwent put them under stress and this brought out willpower as well as increasing further understanding.”

The British Servicemen and women have been ‘fighting’ alongside forces from the USA, Canada, Germany, France, Australia and Holland, among others.

Rapid Alliance was the linchpin of a wider RN exercise, Aurora, which includes 19 RN and RFA vessels, 3 Commando Brigade and 42 Commando, RAF Harriers from 3(F) Squadron and Sea Harriers of 801 Naval Air Squadron.

Army Challenger 2 tanks of the Royal Tank Regiment embarked in Albion and were ferried ashore in her landing craft – the first time in a dozen years that tanks have been carried by a British warship.

“It’s marvellous to see Albion coming into her own in the front line and it’s fantastic to see the ship’s company performing so well and enjoying the benefits of foreign runs after such a busy year,” said Albion’s Commanding Officer, Capt Peter Hudson.

Around 2,000 of the British force consisted of personnel from 3 Commando Brigade, including 42 Commando, 539 Assault Squadron, 79 Battery RA, Commando Logistic Regiment and 59 Independent Commando Squadron.

And as if that wasn’t enough for Brig John Rose, 3 Cdo Bde’s Commanding Officer, to contend with, a battalion of Dutch commandos and a squadron of armoured reconnaissance French marines were also placed under his command.

Among senior visitors to the exercises was Commander-in-Chief Fleet, Admiral Sir Jonathon Band, who beyond receiving updates on the progress of operations, found time to present the Admiralty’s ‘four star’ seal of approval to HMS Albion’s NAAFI.

The admiral went behind the counter to serve some – mercifully not all – of Albion’s 630 crew.

Members of the ship’s company of survey vessel HMS Roebuck were up to their chests in surf in US waters during the exercise – but sadly there was not a surfboard in sight.

They were conducting studies for the amphibious forces taking part in Exercise Aurora, and was sent in ahead of the main task force under the Commodore Amphibious Task Group to reconnoitre a suitable place for landings.

This meant two weeks of hard work for the Devonport-based vessel herself, carrying out surveys offshore.

Her two boats worked inshore as beach survey teams carried out preparatory work, including plotting the gradient profile of beaches earmarked for landings as well as mapping river inlets and neighbouring paths.

The data gathered was transmitted back to the task group staff aboard HMS Albion and the CINCFLEET Weather and Oceanographic Centre to help them plan the impending assault.

Without the data gathered, the amphibious forces would have had limited knowledge of the area they were to operate in.

Although there was plenty of hard work, there was also a chance to play hard as well – and some memorable visits to enjoy.

Invincible made for an impressive sight, her crew in white uniforms lining the decks, as she entered Mayport in Florida.

HMS Cornwall stopped off in South Carolina to sample the colonial delights of Charleston – the city still echoes to the days before independence.

The frigate then moved on to Boston before joining HMS Invincible in New York for July 4 celebrations.

The Royal Marines made themselves at home at the base of their US counterparts, Camp Lejeune in North Carolina.

The sprawling base occupies 250 square miles, is home to 150,000 military and civilian personnel, and generates $2bn for the local economy.

Orlando, Washington DC and New Orleans were all in the itinerary of other ships and units committed to Aurora.