Blackheath is not and has never been a "common". It is manorial waste over which successive owners since earliest times have allowed people to walk freely. In 1871 the lords of the manor willingly transferred responsibility for the surface to the local authority for the benefit of Londoners in perpetuity.
Finally Sir Christopher Wren did not design Morden College in 1695 - another old chestnut which refuses to shrivel.
The Blackheath Society