When Alistair Darling announced his plans to raise the tax paid by higher earners he will have had one eye on the residents of places such as Battersea in south London. The seat, held by Labour with a wafer-thin, 163-seat majority, is a magnet for many well-heeled City workers – and a top Tory target at the coming general election.

Sadly for the chancellor, there were signs on Thursday that the move may have shored up some existing Labour support but done little to persuade others to rally to the party cause.