One originally had difficulty in working out whether Mr Cameron was ignorant, badly advised, or a deliberate, serial liar. But in the end, it doesn't matter. The effect is the same – from his lips venture forward a veritable battalion of lies. The man who chooses to deliver them, and keeps so doing, has to be considered a liar.
He starts his speech with the propaganda line that would be quite at home on the EU's website, telling us that, "the first purpose of the European Union [was] to secure peace", a lie by omission if nothing else as the primary purpose – to the exclusion of all else – is to secure European political integration.
If Cameron can't get past that hurdle, he has nowhere to go. But all he does is talk glibly about different countries not wanting "the same level of integration". He is not listening to his own words. Integration is a matter of degree, for sure, but this is largely a matter of the speed with which different countries reach the same objective. The end objective is a United States of Europe.
Britain, says Cameron, would never embrace that goal, which is rather like him sitting on the train to Brighton and saying he has no intention of going to Brighton – as the stations sail by and his voters implore him to get off at the next stop.
The lie by omission is then embellished when he starts from a deceitful premise, asserting that "we are a family of democratic nations, all members of one European Union, whose essential foundation is the single market rather than the single currency".
The foundation of the European Union, of course, is not the single market – it is "ever closer union". The single market and the single currency are simply means to that end. And therein can be found Cameron's central lie. He wants us to believe that the EU and the single market are, to all intents and purposes, the same thing.
We need progress no further in order to dissect the coming campaign. The effort will be directed towards embellishing that lie, and building on it an edifice of fear, aimed at stopping people looking further.
It is there that Norway inconveniently rears its head. It participates in the single market, but is not a member of the EU. This inconvenient fact destroys his case, so it must be dealt with. Cameron does this with a naked, incontrovertible lie. Norway, he asserts, "has no say at all in setting its rules: it just has to implement its directives".
Not even the Norwegian europhiles claim that. They say that Norway has "limited influence" – true enough inasmuch as there are limits to the influence of every nation on earth. But for Cameron, it is too dangerous to admit that, so he resorts to the outright lie.
The fact is, Cameron then says, "that if you join an organisation like the European Union, there are rules. You will not always get what you want. But that does not mean we should leave - not if the benefits of staying and working together are greater".
But the even greater fact is that, if you join the European Union – and there is no organisation like the European Union … it is unique – you are committed to European political integration. Whatever the benefits, that is the unacceptable downside.
What Cameron is at pains to conceal is that we can have the "benefits" of the single market without the downside of political union. By decoupling from the deadweight of political integration and reasserting ourselves on the world stage, we can actually increase our influence in making the rules.
These essential truths, in my view, lie at the heart of the battle to come. Mr Cameron has today demonstrated the fragility of his case, and exposed his willingness to lie to protect it - backed by the biggest lie of all, that "we will have time for a proper, reasoned debate". That is the very last thing this man wants.
Personally, I feel a deep, wrenching revulsion at knowing that we have an unconscionable liar for a prime minister, and a gut-churning dismay at the thought that we might have to vote for him to get our referendum.
Even to this point, as PMQs conclude, Miliband is refusing to commit to an in-out referendum, so we don't even have a choice of liars. But what a state we are in when that is the only possibility on offer.
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