Just eyeballing the constituency results, it appears that the Conservatives have failed to win any presence in any major city outside London (and, with a couple of gold-plated exceptions, most of the heart of the capital too).
This indicates one thing: David Cameron's bike-riding and wind turbines haven't convinced affluent but liberal-minded voters in large cities that the Conservatives have anything to offer. The Tories have become, and remain, a party of rural and suburban England and Wales (with the exception of the richest parts of London). Their consistent Euroskepticism and discomfort about immigration and contemporary forms of family life stem in part from this. Will they ever be able to connect with people in urban Britain?
If not, PR will be the only way to get stable government in this country. It probably will in any case.