At the bottom of this post is a spreadsheet giving the full notional results for the provisional recommendations, now covering Scotland, England and Wales (I haven’t calculated any notionals for Northern Ireland). We now have recommendations from all four commissions, the England, Scottish and Northern Ireland commissions have completed their first consultation period (the Welsh one is just starting), shortly they will put up all the written submissions they received and allow a further consultation period to allow people to comment on other people’s comments. After that we have the wait for the Commission to produce revised recommendations later this year.
The overall impact of all four Commissions recommendations is to reduce the number of Conservative seats by 7, the number of Labour seats by 28 and the number of Lib Dem seats by 11. This would have left the Conservatives just short of a majority at the last election with 299 seats (though note the important caveats with any notional calculations – these are just how the seats would have fallen if people’s votes at the 2010 election had been tallied on the new boundaries. In reality some people may have voted differently had the boundaries been different).
Of course, these figures are only what would have happened on the levels of support at the last election. It is extremely unlikely that the next election will be a carbon copy of the last one. It is more interesting to see what difference the new boundaries make on the swings each party need to win.
The Conservatives need a swing of just 0.1% to get an overall majority (equating to a lead of 7.4 points over Labour). This compares to the current position where the Conservatives need a lead of about 11 points over Labour to win.
Labour would need a swing of 2.5% to become the largest party (equating to a Conservative lead of 2.2 points over Labour). This compares to the current position where Labour become the largest party when the Conservative lead drops below 4 points.
Labour would need a swing of 5.8% to gain an overall majority (equating to a Labour lead of 4.3 points over the Tories). This compares to the current position where Labour need a lead of about 3 points over the Tories to win.
Hence Labour would still win a majority with a smaller lead than the Conservatives, and if the two parties had the same shares of the vote Labour would still have substantially more seats than the Conservatives. This is to be expected, as only part of the disparity is caused by unequal boundaries, with unrelated factors like lower turnout in Labour seats and tactical voting against the Conservatives also contributing.