Every morning in Las Vegas, Steve Smith kisses his wife and young daughters goodbye, gets in his car, drives 50 minutes down the freeway, past shopping malls and casinos, and goes to war in Afghanistan.

After his eight-hour shift, during which he may have launched missiles against Taliban insurgents in Helmand province or carried out reconnaissance for British troops, Smith gets back in his car, turns the radio to the station Mix 941 so he can relax and drives back to the comfort and safety of his family.

Squadron Leader Steve Smith is one of a new generation of British warriors who commute to combat. They are engaging the enemy not from Kabul nor from Kandahar, but via joysticks and computer screens more than 8,000 miles away, at Creech air force base, deep in the Nevada desert. Smith’s job is to pilot what British and American commanders are calling “the most effective weapon against Al-Qaeda” — the MQ-9 Reaper unmanned drone.

The growing strategic importance of drones was highlighted last week when the CIA recommended that the military increase its use of them in Pakistan to combat the mounting insurgency threat. With a 66ft wingspan, the remote-controlled Reaper can stay airborne for 22 hours unseen and unheard at an altitude of 21,000ft — the only thing limiting its air time is fuel.

For the most part, the “hunter-killer” Reaper is used to survey an area, relaying video images back to mission command to help ground troops understand their surroundings. As its name suggests, though, this drone can also engage the enemy. The Reaper can carry an awesome payload: up to four Hellfire missiles and two 500lb Paveway II bombs, all laser-guided. When the order comes from a troop commander on the ground — “Cleared hot” — the pilots in Nevada pull the trigger.

Smith is a boyish, red-haired 40-year-old from Cumbria and a key member of 39 Squadron, the first RAF unit to fly UAVs — unmanned aerial vehicles. The squadron, which now has about 90 people in Nevada, flew its first Reaper mission over Afghanistan in October 2007, and has since flown almost 400 missions during its 3,800 operational hours. The squadron now flies Reapers 365 days a year, for 10-12 hours a day, weather — in Afghanistan — permitting. Used extensively by the Americans, the Reapers cost about $15m (£10m) each. The RAF has two of them in operation but hopes to have six by the end of the year, allowing it to fly drones 24 hours a day.

The Reaper, built by General Atomics Aeronautical Systems, the American defence contractor, is an improvement on its predecessor — a large UAV called the Predator. It can carry a bigger payload of weapons and equipment, and has proved more reliable (that is, less likely to crash) in operations. Last week The Sunday Times was given a rare tour of the facility at Creech and watched as a 39 Squadron pilot flew a Reaper combat mission over Helmand province, in southwest Afghanistan, where Taliban insurgents have been gaining strength in recent months.

Each Reaper is operated from a small, dark, air-conditioned “cockpit” in a ground control station — GCS — by a two-man crew comprising a pilot and a sensor operator. In front of them they each have computer keyboards and a bank of screens that gives them an immense array of geographical, logistical and tactical information.

Real-time images — including infrared night-time shots — beamed back from cameras on the prow of the planes can show them details as small but significant as whether individual human figures are carrying weapons. The pilots and sensor operators also both have joysticks and throttles — and triggers — similar to those used in normal aircraft and in some video games. Because the concentration and focus needed is so intense, Reaper crews work in short shifts of between three and four hours.

The computer screens have five open chat rooms that the crews use to communicate with troops on the ground, commanders in remote locations and other coalition forces. They also communicate via radio and even use secure internet voice communications.

“It allows us to talk to the ‘customer’, who gets our video feed,” Smith explains. The “customer” is usually a JTAC — joint tactical air controller — a trained combat officer on the ground in Afghanistan, who is watching the video images being beamed from the Reaper on a small field computer terminal in a kit called a Rover — remotely operated video-enhanced receiver — that he carries in a rucksack. It is the JTAC on the ground who usually requests the Reaper reconnaissance and will call it in to strike a target if needed.

Sitting behind the pilot and the sensor operator, looking at the same pictures, are two image analysts. They have usually had experience on the ground in Afghanistan and can help pilots and others looking at the video feedback evaluate what they are seeing, in particular to avoid endangering “friendlies” — Afghan civilians and coalition troops.