CAMP Bastion rises from the Afghan desert like a mirage.

In the midst of a desolate sea of sand and rock, the British have built their largest overseas base since the Second World War.

Visible on the horizon as a series of lookout towers and earth-filled defences, this dusty fortified city is the principal base for Operation Herrick - the UK's effort to bring stability to this lawless corner of Afghanistan.

Within its walls sits a sprawling collection of tents and huts - home to 4,000 people.

It houses aircraft runways and landing strips, a helicopter base, refuelling facilities, workshops, shooting ranges, hi-tech communications, a detention centre, a bar (serving non-alcoholic drinks), a shop (stocked with everything from lads mags to stereos), a DVD library, a tented church, and a fully-equipped hospital, which opened earlier this month.

It also houses the Salonika Lines, home of the Rifle Regiment's Salonkia Company - which includes Oxfordshire's territorial infantry battalion the 7 Rifles - who help guard the base.

Two thirds of the unit are Territorial Army soldiers. Many of the Oxfordshire soldiers are just passing through the base en route to the Forward Operating Bases (FOBs) on the frontline.

The base was built by 105 men from 48 Royal Engineers in just four months.

Army spokesman Chris Fletcher said: "Camp Bastion has the infrastructure usually associated with a small town.

"The complexity of the engineering challenge was enormous; scarce potential for local procurement, tortuous logistical chains from the UK, while the men had to work in dust storms with temperatures of 140 degrees Fahrenheit with a continuous threat from anti-coalition militia.

"Yet they succeeded in building a sophisticated, state-of-the-art desert camp for thousands of troops."

The soldiers sleep in ten-man heated and thermally-insulated tents.

"Bastion is a really weird place," says Rifleman Lloyd Nolan Crockford, from Charlbury.

"We are continually on the go. There is no normal routine of life. But it is home.

"It's good to have everyone around you and the food is good - and there is lots of it."

Captain Tom Barker, serving alongside Salonika Company in 3 Princess of Wales's Regiment, said: "The men call Camp Bastion 'Slipper City', but it's all relative. Compared to Kandahar Airfield it's still very basic.

"It's all tented accommodation and we are living out of sleeping bags on camp beds, and eating with plastic knives and forks.

"It's also very dusty and when it heats up it can be a foot deep in powder. It saps your energy trying to keep weapon systems clean.

"But we do have a Pizza Hut, in a metal container!"

He added: "The men of the 7 Rifles are doing a vital job. The base houses 4,000 people and is a large target. And with flights coming in all the time, we have to provide safety around the clock.

"There have been no attacks on Camp Bastion as yet, but it's only a matter of time, so it's a case of being prepared.

"It's quite tiring but the guys stay alert. They are aware that only a few miles away things are happening.

"But it is satisfying. And we always have good feedback from the population. All the people here want is peace - and that's why we are here."

"The men have had contact with the enemy on the ground, coming under rocket-propelled grenade attack, and have returned fire.

"The conditions out in Helmand are austere but getting better.

"People are eating rations packs and living in holes with sandbags on top. The temperatures fall to -10C at night, and when it rains it floods, leaving them ankle deep in mud. It has also been snowing.

"But this is what infantry soldiers train for. All those wet weekends on exercises in the Brecon Beacons don't seem so bad now!

"Compared to life in the FOBs, Camp Bastion is luxury."

Lieutenant Jon Dolphin, of Salonika Company, said: "The 7 Rifles are providing force protection. The Taliban have always used fear to control the local population. But the vast majority of people just want to live their lives. And we are here to help them do that."

He added: "This is a beautiful country, with fantastic mountains rising straight out of the desert plain. And the sunsets are beautiful. If it wasn't such a war-torn country it would be a great place for skiing and climbing."

Despite the relative comfort of Camp Bastion, many of the lads are itching to get out to the frontline, where they can put their training to use.

"The highlight of coming here was getting out of Camp Bastion," said Rifleman Dan Hobley, from Witney.

"That's why I joined. It has been a real experience. Bastion is not really exciting though. In fact it's quite normal."

Sergeant Deborah Jane Francis, from Wheatley

"I'm the company's clerk, which means I look after pay, allowances, moving and tracking.

"Although I work full-time for the TA, this is my first operational tour.

"I came with an open mind, and didn't know what to expect.

"But everything's very organised.

"I was surprised at how big the camp is and impressed with the set up.

"I've been here since October, but am looking forward to going back home for a break.

"The thing I miss most is being able to walk bare foot on carpets! Also china plates and metal knives and forks.

"My family are very supportive, and worried.

"The level of support back home has been overwhelming, with lots of people sending cards and packages.

"Some included their addresses, and I have been writing to thank them, but others wrote anonymously, expecting nothing in return.

"It's good to know the public is on our side."