A HUGE swathe of Southern California, wedged between Los Angeles and San Diego and flanked by the Pacific Ocean, isn't where you'd necessarily expect to find soldiers from Poole training.

At least not until you realise that Camp Pendleton is the main training facility for the US Marine Corps and a base the size of Hampshire. Big isn't really do it justice.

Thirty gunners from 148 Battery, 29 Commando, Royal Artillery have just embarked on a three week exercise with the Marines here at Camp Pendleton.

Exercise Burmese Chase is all about firepower, small arms, big guns, attack helicopters like the Cobra and the Huey and attack aircraft like the A10 Thunderbolt and the AV8 Harrier.

The exercise aims to improve the ability of UK and US forces to work together in calling for supporting arms in a hostile situation, especially using what's euphemistically called 'air assets' - of which the Americans have plenty.

The primary role of 148 Battery's forward observers, based alongside the SBS in Poole, is as a naval gunfire support forward observation unit.

The Royal Artillery gunners call in firepower from ships, navy aircraft, the Royal Air Force and artillery, when landed in support of 3 Commando Brigade, Royal Marines - artillery, mortars and air strikes.

They are working with marines from the 1st Air Naval Gunfire Liaison Company or ANGLICO.

Commander of 148 Battery, Major Kieran Phillips, says it's an annual exercise which is the undoubted highlight of the training year.

"There are incredible resources here and it's all very centralised. Everything is here in one place, albeit a huge place. The camp is roughly the size of Hamsphire. To get this extent and variety of training back in UK, we'd have to travel all over the country.

"Everyone will gain a tremendous amount from this experience and it cements a very long relationship between the US Marines and 29 Commando, especially in both Iraq and Afghanistan, but also long before that.

"The other key advantage is that it is much easier for the Marine Corps to assemble everything they need for an exercise like this. They own the aircraft and the other assets."

He added: "Being here certainly gives you an idea of the sheer size and scale of the US military although they are under budgetary pressure in the same way that we are."

Meanwhile the soldiers, used to the compact confines of their Poole base, are trying to get their head around a camp of 195 square miles, with 500 miles of roads and around 37,000 military personnel and thousands more civilian staff and contractors.

The camp its own air base, dozens of fast food outlets, its own beach, bowling alley and hospital. It also has a major highway running through it.

Even if the special relationship has been called into question politically in the past week, it will be alive and well on the training grounds of Camp Pendleton in the next three weeks. And around 20 marines will be training at Poole at the end of October.

"We are looking forward to hosting them in Dorset," said Major Phillips.

The marines eagerly waited for their British counterparts with extra supplies of beer as they arrived at the weekend.