This is a good clip of Richard preaching in Piccadilly Circus which is perhaps one of a couple of the busiest tourist locations in London.  In the middle is Shaftsbury Fountain where tourists sit and where they take pictures.  There is always lots of foot trafffic. 

So imaging here in the middle of London is an Ambassador of Christ proclaiming eternal life to the passing souls.  Many listen, many ignore but either way Christ is preached which is the goal of evangelism: preaching Christ to unbelievers that they might be saved.