I was travelling home in my car on the north bound m5 motorway . clear sky and the sun going down a little. the traffic started to slow up due to volume, i looked in my mirror and over my shoulder to manoeuvre and saw this gun metal colour craft just hovering over the edge of the the opposite carriage way , i was astounded ,it was so slim lined and futuristic ,almost like out of the movies star wars,very profiled and the front of the craft almost facing me. things that stood out was it had 3 large very bright green lights under the profiled structure ,i would say about the size of of a large dustbin lid. i had to look away to my driving but looked back over my shoulder it was still in the position for about 5 seconds then just vanished in front of my eyes. i know i had physically witnessed this and the next day started to tell some of my family and friends etc, perhaps that was not wise as i knew they made it into a joke, that i imagined it. i wish it had been in front of me ,i would have attempted to take a video or a photo, my work friend teacher always travel with me ,but of all times not on this day which was a shame as we could not both have imagined it. one thing is that surely other drivers would have witnessed it as it almost hovered over dozens of cars almost driving underneath it but i saw no news reports. my family suggested it may be military with a cloaking device ,but why would craft hover in a field so close to the public highway . one thing i do know is i did clearly see this once in a lifetime out of this world craft and will never forget my experience. i can still picture it even now and could draw it ,so now i am converted to believe i am not the only one to witness close encounters .