What drone could this have been?

Was travelling back from the cinema at around 1am and noticed some lights in the sky. I got a bit creeped out when I realised they were following us, and have since thought it was probably a drone.It followed us for at least 5 miles, and appeared white at first, then red and green, then white and green, then white again and the light died out whilst I was looking at it and it had then just disappeared.I've spoken to somebody with a basic knowledge of drones and said it sounds like a military one. I will add that it was completely silent, and basically kept up with the speed of the car, although sometimes it seemed to be behind us a bit, but at some points during the journey we were travelling at 50mph.I'm just wondering if anybody knows of any drones that this could have been, and I'm wondering if maybe they were following the car as we thought they were somebody else?I honestly have no idea, but it has creeped me out!If anybody could give any input, it would be much appreciated 😊 via /r/drones https://ift.tt/32ftrCQ