Even then, they lost the election. Political practice is that the manifesto is only usable as budgie tray liner once an election is lost. Even the two parties in government abandoned parts of their manifestos when they didn't win outright and had to sign up to a Coalition Agreement. Once they signed that though it was a vastly different story as it was no longer a sales document to convince you to vote for them, it was an actual statement of government intentions.
It wasn't a cock up it was a lie. He went red in the face. Cameron is a known and proven liar. He orchestrated the entire 1992 Tory election campaign, a campaign which afterwards the ever indiscrete Ken Clarke admitted on "Any Questions" was based on lies.
Call it what you like, I don't care and in fact don't disagree.
Point stands though Trojan I was clearly making reference to the last Labour Government, who couldn't find a buyer for the 30% they'd valued at £2 billion, not a none existant line in a manifesto.