I couldn’t believe it when Nicola Sturgeon called for the resignation of Alistair Carmichael, the former Scottish Secretary, over his role in the leaked memo affair.

As readers will recall, the Daily Telegraph published a confidential document during the election campaign that purported to be an account of a conversation between Sturgeon and Sylvie Bermann, the French ambassador, in which Sturgeon said she’d prefer David Cameron to Ed Miliband as Prime Minister. Carmichael has now owned up to leaking the document, which originated in the Scottish Office, but this isn’t the cause of Sturgeon’s outrage. No, Carmichael’s sin was denying all knowledge of the leak when asked about it at the time. For this, apparently, he should ‘consider his position’.

Politicians pretend to be shocked by each other’s behaviour all the time, but this is a particularly shameless example. There’s more than a smidgen of cold calculation behind the white heat of Sturgeon’s indignation. The reason she singled out Carmichael’s alleged dishonesty, rather than his breach of confidentiality, is because she doesn’t want anyone to focus on the substance of the memo. Why? Because it was almost certainly an accurate account of what she said to the French ambassador. More fundamentally, it’s hypocritical of the SNP leader to complain about duplicity, given her party’s conduct in the run-up to the referendum.

I’m thinking of Alex Salmond in particular. On almost every critical point raised during the debate about Scotland’s future, Salmond was deliberately misleading. I’m not just thinking of his claim that he’d received legal advice reassuring him that an independent Scotland wouldn’t need to reapply for membership of the European Union. When the Information Commissioner ordered the Scottish government to respond to an FOI request to disclose the advice it had received, Salmond’s ministers spent £19,452.92 of public money appealing the decision, only to admit later that the ‘advice’ was a figment of Salmond’s imagination. So the First Minister misled the Scottish people on this point and spent taxpayers’ money to try to conceal the fact.

Then there were the SNP’s fictitious claims about the economic impact of independence — and I’m indebted here to the blogger Kevin Hague, who has devoted years to unpicking the SNP’s rhetoric. For instance, there was the assertion that Scotland sends more money to Westminster than it gets back, thanks to North Sea oil.

If you factor in its share of oil revenue, Scotland has been a net contributor to Britain’s coffers in three of the last 15 years. For the other 12, oil hasn’t been sufficient to offset the fact that the Scottish government spends £1,450 more and raises £250 less per person than the rest of the UK. This makes Salmond’s claim, repeated ad infinitum, that ‘oil is just a bonus’ and Scotland could get along perfectly well without it, even more absurd. If you add the £1,450 and £250 together, you get a per capita gap of £1,700, which means that, without North Sea oil, its deficit would be £9.1 billion higher than it is as part of the UK. It turns out that oil revenue is critical to offsetting the deficit gap, which is presumably why Salmond wildly over-estimated it in the SNP’s white paper on Scotland’s future. In it, he claimed that revenue from North Sea oil in 2016/17 — the first year of Scotland’s independence — would be between £6.8 billion and £7.9 billion. In fact, it’s likely to be around £600 million.

If you deduct the £600 million from the £9.1 billion, that means Scotland would be facing an annual deficit gap of £8.5 billion in its first year of independence and there’s no reason to think that would change over the next ten to 15 years. In order for Scotland to be better off out of the UK, oil revenue would have to increase by several thousand per cent, or the Scottish economy would have to grow by a faster amount than the rest of the UK — around 15 per cent faster. For Scotland to wash its own face would mean massive public spending cuts. Far from imposing austerity on Scotland, the British government is saving Nicola Sturgeon from having to find Greek levels of savings. Who would have thunk it?

The SNP is, by some margin, the most dishonest party in Britain. For its leader to call for Alistair Carmichael’s resignation because he leaked a memo is laughable.