The principle of this is great, but the final map tries too hard to make all of the regions a consistent size and ignores existing physical, political and cultural boundaries. For example, your Essex region is cut in two by the Thames Estuary, and a toll bridge. This could make movement between the two sides really impractical and which side would you put your administrative base in? London is massive and you might want to split it up but that completely ignores the fact that huge number of people on the outskirts commute into the centre, and therefore it makes sense in terms of tax collection, transport, energy ect. for it to be one region. Also, by making areas more consistent in population there is an even greater disparity in area. A massive region like Deira would spend a huge amount more money on roads, railways, policing, schools, ect, which somewhere like Northumbria has a lot less land for new homes and infrastructure. It makes sense for Tyneside to sit within a greater Northumbria region, rather than dividing the city and the country. Finally cities have much greater economic activity, the GDP of London is around a 1/3 of the GDP of the whole country, so the rest of the country will suffer massively if London are able to keep and spend their own tax revenues.