Should constituency boundaries be left to politicians to decide? Surely not, however well intentioned they are, there will always be a temptation to manipulate them in an attempt to divert votes in favour of their own party or away from the opposition. Instead it should be left to mathematics and geography with the politicians only involved in ensuring that the rules are adhered to.
In truth the revision of constituency boundaries is relatively free from political interference, though any changes need to go through parliament and can therefore fall. The Government can decide whether or not to bring them to the house and the other parties can decide whether or not to vote for them. This, in my opinion, is wrong for the reasons I have already given.
The latest review was through the Parliamentary Voting System and Constituencies Act, when the four national Boundary Commissions were asked to undertake the 2018 Review of constituency boundaries to equalise the size of seat both within and between the four nations of the UK. There were two consultation periods. Although the proposals were put to Parliament they were not brought forward by the Government for approval and so have not been implemented.
Here are my thoughts. There are 650 seats in Parliament and so each constituency should have about a 650th of the population. Getting exact numbers will be impossible and so perhaps a range should be agreed, such as between 95% and 105% of this number.
Each current constituency will be stored as a polygon using GIS tools. Using location information on households with voters (and the number of voters) the centre of each polygon will be calculated as the point that is the average distance from the voters in that consistency. This will be known as the central point.
Starting from this central point, each constituency will have to grow outwards, if it is below the range, or shrink inwards if it is above the range. Computing power will be used to redraw the polygons taking into account some basic rules, such as no postcode will be split across two constituencies (there are about 100 properties in my own postcode).
Once the calculations have been done the constituencies can be agreed. The central point for each constituency can then be reconfigured and will act as the basis for the next review. It is a simple (?) question of getting the algorithm correct and then the process can be run as often as you like, in the middle of each government for example.
This process would also allow for a reduction in the number of seats in parliament, reduction from 650 to 600 has been suggested, by removing the largest and smallest constituencies and allowing the calculations to do their thing.
Democracy relies on fair representation and this should be based upon relatively equal constituency sizes without interference or assumption of the politics of the electorate.