I googled "countries by population density" The UK is way down in 49th place. So hardly full. There is an "infrastructure" issue but no goverment has the balls to really tackle it by encouraging more dense housing, energy conservation, and force people to use public transport/ more sustainable means of travel. I may be wrong but making the country poorer will only make the problem worse not better.
In my own little town, that is on the edge of the Peak District National Park, a new housing development is just being finished. They are all detatched, it is utter madness.
http://statisticstimes.com/demograph...on-density.php