The fuzz did back-track on that statement (maybe under heavy leaning from Earl Grayling). Difficult to see how you could get to 93 witness statements from employees within the airport if it was all BS.
Equally - it's difficult to see how you could defend the entire approach/take-off air-space (not just the airport perimeter) in a reliable way in day/night/rain/fog etc. As many have said on here, it is reasonably easy for a determined technically competent person to make their own quad-copter with a 30 min battery life, with an autonomous GPS system that would take-off, route over an airfield approach, and then head back to a pre-determined location. No radio-traffic or comms involved - so nothing to detect or block/jam.
Assuming a radar-based detection system (mitigates rain/fog etc) could detect, then the challenge is applying kinetic energy to disable the device. Again assuming you don't care where it lands/crashes! Directed energy weapons might seem an obvious choice but not that clever with aircraft in the vicinity.
The Russians apparently are considering deploying their own counter-drones - presumably directed onto target by a separate detection/tracking system. But that would still mean significant disruption and diverted flights whilst drone-dog-fight takes place in the skies. And it wouldn't appear certain that it would take out another drone 100% of the time.