The Tories have repeatedly lied during this campaign, cleverly saying things that sound true but simply aren’t A particular type of deception served Vote Leave exceptionally well

In the past week, the Conservatives have claimed that Labour plans to increase government spending by a trillion pounds (they don’t), that Jeremy Corbyn will extend the free movement of people from the nations of the European Union to the rest of the world (he won’t), and that Labour plans to hold two referendums in 2020 (no such luck).

What all these fibs have in common is, like any good political lie, you can’t rebuff them without reiterating the central point. Labour don’t want to increase public spending by a trillion – but they do plan to spend around £100 billion on infrastructure and the public services.

The Labour leadership has rejected the policy passed by Labour activists to open up the United Kingdom’s borders – but Corbyn has hinted he will retain the movement of people within the European Economic Area.

Labour has no plan to hold two referendums in 2020, but they are committed to holding one referendum – on the United Kingdom’s membership of the EU – and the reality is that to form a government, they would have to reach some understanding with the SNP, who want to hold a second referendum on Scottish independence next year as well.

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This particular type of deception served Vote Leave exceptionally well, the victorious pro-Brexit campaign where many of Boris Johnson’s key aides made their names. It is not now and has never been true to say that we sent “£350m a week” to the European Union. But the rebuttal – that we in fact sent a still pretty hefty £250m a week – hardly reassured voters who thought the money better spent here at home.

But the difference between Vote Leave’s gambit and the Conservatives’ falseheoods is that the £350m a week porker worked because it went with the grain of a narrow majority of voters’ pre-existing conceptions about the European Union. They thought – and in many cases still do – that we pay a lot of money to be a member of the bloc, and that we could better spend that money ourselves. Secondly, while £350m is a lot of money – more than most of us will ever have – it is a tangible amount of money, the amount of money that a film might cost to make, or Manchester City might spend on players.

But no-one knows how much a trillion actually is – I don’t mean as in the dictionary definition of “how much is a trillion?”, I mean that we have no purchase on it. Why is a trillion bad, but Labour’s planned spending spree less bad? What about the Tories, who themselves plan to increase public spending by tens of billions themselves?

The free movement lie has a different problem. Rightly or wrongly, people regard giving £250m a week to the EU and giving £350m as a distinction without a difference – in either case, you’re handing over millions of pounds. But even people who oppose the continued free movement of people within Europe don’t regard it as one and the same as the free movement of people across the whole world. The only people who do quite like the idea.

Political lies work best when they do two things: if the truth is almost as painful for the party in question as the deception, and if they feel, if not actually true, at least close enough to the truth as to be revealing. Jeremy Corbyn had a good one of those this week, when he said that had the floods happened in Surrey, the government would have declared a “national state of emergency”.

The big problem here is that there hasn’t been a national state of emergency since the middle of the 1970s. But the line works because it speaks to a statement that a large number of people believe to be true – that the Conservatives don’t really care very much about people outside the wealthy south of England.

That said, the good news for the Tories is that an electorate which is increasingly tired of and bored by politics might just be willing to swallow the campaign’s biggest lie of all: that a vote for the Conservatives will “get Brexit done” and allow the country to move on to other things.

The truth is that whether we go ahead with it or cancel it, we will have decades of arguments about Brexit – whether in negotiating the new trade deal with the EU, or among the large group of Leavers who will want to seek a third referendum, and a fourth if necessary.

But Johnson’s get Brexit done lie feels true – and that might just be enough to get him over the line on 12 December.

Stephen Bush is political editor of the New Statesman