Travelling at night in a coach when I noticed a star that seemed to be dancing. I thought it may have been because of the window glass vibrating so I stood up and opened the sliding section above so i could see it without looking through glass. I told others on the bus and we all watched it ascend and descend and move at angles to the north and south. It just looked like a star but it moved very fast in a zigzag fashion for up to five minutes as we traversed the large wide open valley. It then dropped at high speed at around 45 degrees to the south east and disappeared behind the outline of a series of hills. Moments later there was a bright flash which outlined the hills from behind.Everyone on the bus witnessed it and all discussed what it may have been throughout the rest of our journey. All we could agree on was that it was was a UFO. After all was said and done this was the most discussed and thought of event of that days excursion.