The Ministry of Defence has signed a contract worth around £100 million to test the UK's Protector aircraft.
It will be the first remotely controlled aircraft capable of attacking targets anywhere in the world and is expected to be in service with the Royal Air Force by 2024.
Arriving in the UK for the first time at RAF Fairford last summer, Britain is to have 20 of the aircraft, the design of which builds on the exiting Reaper drone system.
Under the new contract, General Atomics will test the aircraft and report back on its performance in advance of the aircraft’s introduction to the frontline.
The drone, which has also been known as the MQ-9B SkyGuardian, will be fitted with the Brimstone missile and Paveway bomb systems and will use onboard sensors to avoid other aircraft.
Protector will become fully certified to fly missions from RAF Waddington, the base already responsible for operating the Reaper aircraft.
The new aircraft will replace the Reaper and become the world’s first certified Remotely Piloted Air System, meaning it can operate in civilian airspace.
Protector will be able to fly consistently for up to 40 hours and will be deployed across the full spectrum of operations, including ISTAR, search and rescue, flood prevention or disaster response missions.
The fleet will also have advanced anti-icing and lightning protection, providing the RAF with the flexibility to operate in adverse weather conditions.
Defence minister Anne-Marie Trevelyan said: "Our intelligence-gathering and surveillance capabilities will be critical to staying ahead of our adversaries as we enter an era dominated by grey-zone warfare.
"This contract represents a welcome step towards our world-beating Protector aircraft reaching the frontline, giving us the upper-hand against our adversaries."
The first Protector aircraft will be delivered to the RAF in October 2021.