@Charles Manning - "Like any other manufacturer/service provider, they sell what the punters buy"
No, they sell what the suckers will believe.
For example the 2010 Tory Party Manifesto said "We will stop the forced closure of A&E and maternity wards, so that people have better access to local services, and give mothers a real choice over where to have their baby, with NHS funding following their decisions."
But in 2012 the Tories attempt to force the closure of the A&E and maternity ward at Lewisham Hospital, however, fortunately, they were defeated in the courts.
That's just *one* small example of what lies politicians will peddle to get people to vote for them, knowing full well that, once they're in power, they can do what the hell they like for the next four or five years before they peddle a *new* set of lies (and bribe people with their own money) to get them to vote for them again.
This makes a total mockery of the concept of democracy.