I was driving back from Brighton, East Sussex (for a friend's baby shower) back home to Gloucestershire. After coming off the motorway at Swindon, I took the A433 from Cirencester towards Tetbury to get to my home near Dursley. I kept to the main road as my phone battery had died and I didn't want to get lost on the tiny back roads in the deep, dark Cotswolds, surrounded by woods and fields. It had been a really hot day so I had my windows rolled all the way down and was enjoying the cool night breeze listening to the radio. I was relaxed but focused on driving, noting the only car on the road with me was keeping a steady distance of around half a mile behind me. I regularly checked my rear view mirror to check the two tiny points of its headlights were still there, and it gave me a sense of safety to know I wasn't completely alone so late at night (10pm-ish). The next time I checked my rear view mirror, I was surprised to see a large white circle, size of a football, glowing like a headlight, following directly behind my car. My first thought was that the car had caught me up very quickly indeed and I was confused how it had done that. But then I realised it must be a motorbike as there was only one headlight and motorbikes can zoom along faster than cars. However, I could hear no chugging or buzzing noise one would expect to hear from a motorbike engine at full pelt. I noted I was going 50+mph and this thing was keeping up with me. Just as I turned my radio down to silence, my brain really confused, the light circle moved to overtake me on the right and I saw it come into view in my right side mirror. I looked at it several times whilst keeping an eye on the road ahead of me, wondering what manoeuvre it would make as it wasn't overtaking. And then it simply vanished. Disappeared as quickly as it had appeared. I kept driving, utterly baffled. I noticed the other car a half mile behind me was still cruising along in the distance. I replayed what had happened in my mind over and over, trying to work out what I had just seen, but I could not come up with an explanation. After I while I understood I might have had a paranormal experience and I was thrilled, and felt very honoured. Back home, I did a bit of research and was able to identify what I had seen was an orb of light. On reflection, I've wondered the reason this orb followed me. I think it was just checking me out. I didn't feel threatened or scared by its presence, maybe it was escorting me for a bit to make sure I was okay on my own... I don't know. Lasting thoughts: it was awesome and I feel blessed.