The area was solidly Conservative from 1955 until a boundary re-organisation in 1997.

BBC: Candidates line up for Croydon North by-election

Even if every Conservative MP votes for the boundary changes (which is doubtful given the varied local impact), the Tories could still be out-voted by Labour and the Liberal Democrats - unless smaller parties vote with the Prime Minister.

BBC: Maps, maths and boundary changes - MPs digest details

David Cameron told Welsh Conservative MPs he didn't want "any silliness" when the Boundary Commission published its plans for new constituency boundaries.

BBC: Breaking down the boundaries

Two West Midlands Conservative MPs have said they are worried by the size of a new constituency, proposed by the Boundary Commission.

BBC: MPs question size of new constituency