Can anyone identify this please?

This morning I got a glimpse of a bird of prey, but i am unsure what it was. I was travelling through the peak district on a bus and it flew just above my bus and glided slowly across the fields on my right just a few feet from the ground, when I lost sight of it, due to traveling. It was a dull day so i only saw the top of it which was dark, it had broad wings that were somewhere between 6 and 7ft in length. It seemed to fly like a buzzard, although it appeared much bigger, probably red kite size yet it's colouring didn't stand out nor did it's fork tail. So I'm unsure, anyone have any ideas?