Amazon drones are reportedly being tested at multiple UK sites

Amazon is on a mission to put tens of thousands of delivery drones in our skies so that it can deliver DVDs and books to its most loyal customers in less than 30 minutes.

But before that can happen, Amazon first needs to assure regulators that its drones aren't going to go crashing into people, buildings, cars, and basically anything else you can think of. As part of those efforts, it's currently carrying out drone delivery tests on sites around the world.

This summer, Amazon Prime Air cofounder Daniel Buchmueller told a room full of journalists at an event in London that Amazon's largest outdoor drone testing site is in the UK, without specifying exactly where that site was.

Filled with curiosity about the site's size and location, we got in touch with Amazon's PR team in the hope of finding out more but they weren't willing to share any details. "As I'm sure you can appreciate, we do not disclose the details you requested," said an Amazon spokeswoman at the time.

Just over a month later, and after several tip offs, we found the drone test site we'd be looking for on a farm just outside Cambridge, which happens to be where Amazon has an R&D lab. Some publications made follow up visits to the site and the Daily Mail managed to get photos of Amazon's drones in action. Amazon has now built a wall of hay bales around the site to conceal what it's doing and stop people looking in, and the story has gone quiet.

But a new piece of information emerged last week from local newspaper Cambridge News. The newspaper, which was given the first and only media tour of Amazon's drone lab in Cambridge, wrote that "Cambridge is one of a number of testing sites in the country."

Cambridge is one of a number of testing sites in the country.

We immediately contacted Amazon to try and confirm the sentence but after several emails the secretive Amazon drone PR team is yet to respond to that particular point, meaning the company could well be testing its unmanned aerial vehicles across the UK.

Amazon founder Jeff Bezos revealed plans for Amazon Prime Air in an interview on "60 Minutes" in December 2013.

The drones will use GPS coordinates to locate their delivery address and fly to a maximum height of 400ft, before identifying a marker to land at. They will be automated, but will each be monitored by a safety operator on the ground who will eventually watch several drones at the same time.

If you have any further information on Amazon's delivery drone tests then please contact sshead@businessinsider.com.