AP Photo

Nobody loved Bowater House in Knightsbridge. The demolition of this late-1950s, modernist mess in 2006 was greeted with general relief. Yet it did have one virtue. Through its core was cut a wide opening for a roadway that gave us all a view of Hyde Park and of a sinewy, thrilling Epstein sculpture of a family group, urged on by the god Pan and racing on to the green sward. There is no such large opening in One Hyde Park, the building that replaced Bowater House. Instead, Pan has been relegated to the end of a much smaller public road that has been intimidatingly designed to look private. The great people’s invitation into the park has been lost. The public realm has not been abandoned altogether, however. At ground level there are shops, punctuated by some very limited...