By Gordon Corera
BBC News Security Correspondent, Nevada
The Reaper supports coalition troops on the ground
The BBC has been given an inside look at Britain's latest weapon in the fight against insurgents in Afghanistan and Iraq, the Reaper.
Out of the blistering desert sun emerges the Reaper, the latest in unmanned aerial vehicles.
Sweeping in over the mountains with its distinctive profile, it is piloted remotely. But just how remotely is a surprise.
The Reaper, like its smaller but better-known predecessor the Predator, is used extensively in operations in Afghanistan and Iraq.
But its missions are controlled from a US Air Force Base in the middle of the Nevada desert, just an hour from the bright lights of Las Vegas.
Outside Creech Air Force Base sits the small town of Indian Springs with its gas station and Moe's Trading Post, selling Native American souvenirs.
But behind the barbed-wire fence are a series of hangars housing the Predators and Reapers as well as the all-important Ground Control Station which acts as a nerve centre wherever they are flying.
It is not just the US flying from here. In one corner of the base, the Royal Air Force ensign flutters in a light breeze, signalling the presence of 39 Squadron.
Britain's fleet is small. It did consist of two Reapers but one crashed in Afghanistan in April.
The technology on board is so sensitive that a British special forces team was sent in to recover key items before the wreckage was blown up to prevent it falling into the hands of the enemy.
The other Reaper currently flies in Afghanistan and we were given the first access to one of its missions.
The day began with a briefing on the latest intelligence on the ground and an outline of a plan to look at a convoy route in Afghanistan.
The Reaper was tasked with using its sensors to look for Taleban activity or improvised explosive devices on the route.
In many cases it also works with other aircraft in providing support to coalition troops operating on the ground who want to know what is around a particular corner or how many Taleban fighters might be moving inside a compound.
The operators in Nevada can talk directly to a forward air controller on the ground to provide them with live information and updates.
After the briefing is over, we follow the pilots across the base to the Ground Control Station. Its secure inner chamber acts as the virtual cockpit for the flight.
Inside the small, darkened room, an array of monitors feed back live information collected by the advanced sensor ball which protrudes from the belly of the Reaper.
It can provide video and infra-red footage as well as other capabilities the military would rather not talk about.
Inside the room, it is quickly apparent that the mission has changed.
The Reaper is now watching a Taleban compound somewhere in Afghanistan's Helmand province, although the operators decline to provide any more specifics other than it is "fairly high priority" for supporting troops on the ground.
One pilot manoeuvres the Reaper around the target while the other operates the sensor equipment on board which is sensitive enough to see an individual and if they are armed.
Both use joysticks which look little different from the type you would expect to see on video games. But those operating the vehicles are adamant that the sense of distance and remoteness - and the lack of personal danger - does not affect their sense of involvement in what is happening in the field.
"You really do feel very much part of the operation, part of what's going on, especially when you talk to the guys on the ground. You can hear them if they are taking fire," Wing Commander Andy Jeffrey says.
"I feel almost like I'm there," he says.
A flashing blue light indicates the mission is entering a more critical phase and we are quickly ushered out as the tension level noticeably rises.
The US has long been arming its Predators and now the newer Reapers and has used them against targets ranging from insurgents planting improvised explosive devices in Iraq to the most senior al-Qaeda leaders in Pakistan's border areas.
The first high profile Predator strike came against an al-Qaeda leader in Yemen in 2002.
Most of the vehicles are fitted with a combination of hellfire missiles and 500lb laser guided bombs, comparable to the payload of an F-16.
There were a total of 11 Reaper and Predator strikes this April alone. In most cases, the target doesn't hear the Predator or Reaper coming.
Some of these attacks, notably in Pakistan have proved controversial because of civilian casualties and the US will not comment directly on individual missions.
But those in charge believe the vehicles offer particular advantages. "It's not the weapons. It's the persistence. It's the unblinking eye - how long you can spend over the target," explains Colonel Chris Chambliss, who commands the US fleet of Predators and Reapers.
He believes the ability to conduct long surveillance of a target makes civilian casualties less likely when bombs are dropped.
The ability to send live images to analysts around the world also makes it easier, he argues, to decide collectively whether or not to strike a target based on how likely civilian casualties might be.
During our visit to the base, the British Ministry of Defence also confirmed the RAF is now arming its Reapers and has already used its weapons system.
"Whether a mission is armed is operationally sensitive and what arms are carried on each specific flight is mission specific," explains Wing Cdr Jeffrey.
"We cannot comment on specific operations but can confirm that an RAF Reaper used its weapons system," he says.
In the coming years, unmanned aerial vehicles are likely to become an even more important feature in modern warfare.
But the RAF and the pilots who fly them are also clear that whatever their value there is no sign of them yet replacing the more traditional men in their flying machines.