Reading about the history of preaching, I tripped over these comments by W.J. Torrance Kirby:
…unlike the royal Abbey of Westminster, St Paul’s was always perceived as belonging more to subjects than to princes, and this peculiar status was to acquire increased significance over time. From the earliest records it is clear that the cathedral churchyard was one of the favoured settings for popular protest, a place where public grievances could be aired. For centuries this was the meeting place of London’s folk-moot; royal guarantee of the liberties of the City was proclaimed here in the reign of Henry III; Paul’s Cross was also a rallying point for adherents of Simon de Montfort’s rebellion. In the sixteenth century this place was the acknowledged epicentre of a series of revolutionary events where matters of religious identity were concerned. (W.J. Torrance Kirby, ‘The Public Sermon: Paul’s Cross and the culture of persuasion in England, 1534-1570’, Renaissance and Reformation 31 (2008), p. 6)
Maybe, by chance, Occupy London ended up in just the right place?