I wonder what you all might make of the following? I was joining downwind LH from about 20 degrees off, shortly before the downwind position - this was a high wing and I had a good view of movements coming off the active runway, or so I thought. I had seen an aircraft lift off and had maybe fixated on it a little too much. Right as I went to transmit 'downwind' I saw a dark coloured classic aircraft passing close behind me. It had lifted off and turned left early so that it passed exactly through the downwind point at circuit height. Don't you think that is a potentially dangerous thing to do at an airfield? The one place that you are sure to find another aircraft is at the downwind point. I am told that the view from this type is quite poor and I am not certain that he saw me. If he did see me, then he was very reckless in judging the distance to pass behind.