It's a significant cause, though internal markets, excessive management and privatisation by stealth also contribute heavily. All parties are indeed guilty in that regard. For shame.
It's sweet of you to omit to mention the LDs but you can add them to the list of parties of government responsible for this state of affairs. Sometimes people (wish us to) forget they were willing collaborators in government for five of the last ten years. If we're casting around for blame, as indeed we should, let us be fair about it and ensure all actors in the tragedy are named and shamed.