In the 60's I recall a Yorkshire mob taking over the Devonport End for the whole match. I
think it was Huddersfield but not sure (certainly not Leeds). All of them were over six foot, with scars, big boots, muscles and no brains.
But talking of Leeds, bless 'em..... I actually stopped going to any matches for a few years around the late 70's due to their fans. I was living in the Midlands at the time. I went to watch Coventry at home to Leeds. Coventry being the first all-seater stadium designed to do away with crowd trouble!
Within 5 - 10 mins of kick-off the Leeds supporters were throwing missiles. This was not in response to anything on the pitch - they had clearly gone prepared because they must have used spanners to unbolt the heavy wooden seats and not only were throwing the heavy bolts but also the seats through the air onto the crowd in front of them. That nobody was seriously hurt was down to luck!!!! Live football was not worth dying for so I stopped going. It was incidents like that which enabled Thatcher to put pressure on clubs to clean up their act. Loss of atmosphere maybe but a safer environment certainly.