It’s an interesting picture. I did, originally, think it might just because because we did better against the Lib Dems than against Labour (and Lib Dems are stronger in the south west of London).
But even that’s not true. While we had a great success in Richmond, we didn’t match that against a Lib Dem council in Sutton – where they strengthened their hold.
What does seem to have happened that the ‘traditional’ Conservative block of stable Conservative councils (Wandsworth, Westminster and K&C) seems to have been joined by Hammersmith and Fulham.