I touched on the issues around the proposed Brighton Pavilion
However, start by turning to the west of Brighton Pavilion, to the proposed Hove seat, which is actually the current Hove with the Brighton & Hove City Council ward of Regency picked up from the current Brighton Pavilion.
Colin Rallings and Michael Thrasher drew up the notional results of the 2005 general election based on the real 2010 constituencies. For Hove they got:
and for Brighton Pavilion they got:
The real results for Brighton Pavilion in the May 2010 general election are:
The real results for Hove in the 2010 general election were actually:
The notional reults for the proposed Hove are:
If we take the difference, we get:
This is, as far as we can calculate it, how the good people of Regency voted in 2010. We then divide each party's votes by the number of votes they got across Brighton Pavilion as a whole and multiply that by the notional 2005 result calculated by Rallings & Thrasher, to work out how Regency voted in 2005:
We now add those to the notional 2005 results that Rallings & Thrasher calculated:
So, this is the notional 2005 Hove result based on the 2015 boundaries. If the 2010 election had been fought on the 2015 boundaries, then these are the results that Labour and the Conservatives would have been using to indicate it was a 2-horse race.
The next step is to take how we have calculated the Regency ward to have voted in 2010 and subtract that from the real 2010 result for Brighton Pavilion:
These figures are how that part of the current Brighton Pavilion that remains in the proposed Brighton Pavilion voted in 2010.
The motional results we have for Brighton Pavilion are:
If we take the difference, we get:
What's causing the difference? It's because the proposed Brighton Pavilion takes in a Brighton & Hove City Council ward - Moulsecoomb & Bevendean - from the current Brighton Kemptown. The low Green vote in that ward could mean that the voters don't give a stuff about polar bears. Or it might mean they were living in a constituency which the Greens were not focussing on as they concentrated on (successfully) getting Caroline Lucas elected as MP for Brighton Pavilion.
And if the 2010 general election had been fought on the proposed 2015 boundaries then this would be a ward that the Greens would have extensively campaigned in to get Lucas elected.
Rallings & Thrasher calculated the notional 2005 results for Brighton Kemptown to be:
The real 2010 results were:
As we have done before, we can take the 2010 results for Moulsecoomb & Bevendean and divide them by the 2010 results across the whole of Brighton Kemptown, and then multiply them by the notional 2005 results that Rallings & Thrasher calculated. What we then get is how the good people of Moulsecoomb & Bevendean voted at the 2005 election:
The final step in this lengthy calculation is to take the notional 2005 results for Brighton Pavilion that Rallings & Thrasher calculated, subtract the 2005 Regency vote and add in the 2005 Moulsecoomb & Bevendean vote:
This is the notional 2005 result on the 2015 boundaries. If the 2010 general election had been fought on the 2015 boundaries then these are the results the parties would have been using as the results of the last election. And it gives the Greens a higher mountain to climb.
At thr 2010 general election, the Greens increased their share of the vote by 9.42%, the Labour vote decreased by 7.48%, the Conservative vote increased by 0.40% and the Liberal Democrat vote decreased by 2.22%. If we assume that the notional Brighton Pavilion would have seen the same shift in vote, then we get the Greens on 29.29%, but Labour winning on 30.47%.