Briefly - Speakers Corner is a part of Hyde Park where people can turn up and have a rant about what ever they want.
For the most part, it is very much those with a religious bent that were doing the talking although the wars did come into at one or two points.
If you've ever seen the film "Monty Pythons Life of Brian" - there is a section where "Reg" falls into a group of "speakers" and comes with with such classics as "consider the lilly" and "blessed are the cheese makers"
It was very much like that.
The main characters for us were "the Cowboy", "Lenin", and "the chap by the lamp post". Fringe characters also existed such as the man in the apron, the elderly lady whose rants would have got her arrested any where else and of course our favourite who didn't want his picture taken and accused Sandy of being "a secret picture taker". You do not turn up at speakers corner and engage the main players of the day and then complain about having your picture taken. It's like being the B&G coming out of a church to find people taking lots of pictures of you and accusing them of "being secret picture takers". Many were apparently regulars and well known to Alan who uses this location as source material.
Some of the comments were thoughtful, some considered, some just plain rude, others very funny and the rest was either so far off the beaten track or so in your face aggressive it was jaw dropping.
This is just a brief explanation, but i hope the others will come in with their take on the day.
Hope this helps a little bit.