Does this mean the U.K. has a competitive advantage? “Possibly,” Corbett says. “With small [UAS] you want to fly them where the use is. If it's test and evaluation, then yes, maybe—that's one of the reasons the additional airspace was created around [the NAC]. But the big thing is it's not a race, and the U.K. isn't going to forge ahead of anybody. Whatever you stick in the air affects international air traffic, so it's all got to be done as harmonized international work.”

Such work is ongoing—a plethora of different groups convened under different auspices, often involving the same subject-matter experts, meet regularly and are making progress. But there are a number of differences between nations that make harmonization tricky. Corbett points out that, in general, U.K. law often works on the basis that if something is not prohibited then it can be done, whereas the tendency in other parts of Europe may be to only consider an activity to be legal if it is specifically permitted.

In the U.S., Customs and Border Patrol unmanned aircraft are considered as state-operated aircraft, and are treated similarly to military UAS, while in the U.K. police and fire services that have used UAS have been dealt with under civilian airspace regulations.

The missing ingredient for all airspace integration efforts is operational data. Experience gained by western militaries operating UAS in combat zones is not seen as likely to help make the case for safe civilian operations, even when—as at Kandahar—remotely piloted aircraft are largely treated as equivalent to civilian and military manned aircraft. Corbett is optimistic this is one area where the U.K.'s regulatory work may provide some answers.

“Hopefully [the segregated airspace blocks for larger UAS] will produce a body of evidence which can be used elsewhere,” he says. “I want to see stuff up there, building time, proving to the world that they don't fall out of the sky, and having manned aircraft interact with them in a controlled manner.”