Adrian Tinniswood admires an example of Wren's post-Fire reconstruction but despairs at a more recent act of demolition
My wonder is St Stephen Walbrook in the City of London, designed by Sir Christopher Wren and finished, apart from the steeple, in 1680. To be honest, although it is the finest of Wren's post-Fire City churches, the exterior is nothing to write home about. Time has hardly been kind to the interior either – Wren's box pews have been replaced by circular seating and a travertine altar hewn by Henry Moore, turning the central space into a stage-set for an embarrassing group therapy session. But just look up and marvel at the soaring light and ambiguous geometry of the ceiling in which dome, octagon, cross and square vie for supremacy. Then you know exactly what CR Cockerell meant in 1856 when he described St Stephen's as "a bubble of unexampled lightness which has … not yet blown away".

There are plenty of buildings I dislike, but oddly enough, the one I hate with the necessary vigour doesn't exist yet. My blunder is whatever heap of deadly suburban dross is erected on the site of Greenside, the modernist villa by Connell, Ward & Lucas in Wentworth which was demolished last November. The loss of that grade II-listed house impoverishes everyone who cares about architecture and I hope Amyas Connell's ghost haunts its successor for all eternity.