There was a report a few weeks ago that Alistair Darling was uncomfortable about having to repeat the claim that “up to 500,000 jobs” had been saved by government interventions since the credit crunch.

The Mail on Sunday claimed that Darling had argued against Gordon Brown’s entreaties to repeat the figure more often.

You may remember that the chancellor first made the claim in the Budget. Then Gordon Brown in July upped the ante by claiming the government had saved “at least 500,000 jobs.” The figure was always a bit debatable because it included jobs saved by interest rate cuts and quantative easing, both of which were carried out by the Bank of England.

Back in September I asked the Treasury press office half a dozen times to give me more detail about the number, in particular the lower level of the range of estimates. No one could tell me, as I blogged here.

Now Alex has obtained the Treasury’s original guidance to ministers back in April. It was impossible to give a definitive number, said officials. But it would be reasonable to use the figure of “250,000 to 450,000″.

So not only was the lower estimate half the figure used by ministers. They also rounded 450,000 up to 500,000 to give a nice, round and not altogether kosher figure.

UPDATE

Alex points out that at least the methodology used to reach the range of estimates was sound. The Treasury did not take account of the UK’s generous automatic stabilisers (for example, tax credits).

An excruciating moment after PMQs when the Speaker announced the appointment of Sir Ian Kennedy* as chair of the new IPSA expenses regulation body.

The announcement - and the fact that the professor will be paid up to £100,000 a year - was met by MPs with catcalls, jeering and laughter around the chamber. As Sir Ian was described as an “eminent” candidate, there were more hoots and jeers. At least one red-faced MP was jabbing his hands in the air with disgust.

This will not look good at all on television tonight.

* He chaired the inquiry into the Bristol Royal Infirmary scandal

So many numbers are flying around that you might not have spotted today’s real news on RBS.

That is, the government has wiped the slate of an estimated £9-£11bn of tax liabilities owed by the giant bank.

In private Treasury officials suggest that the figure is closer to £4.5bn. But the larger figure has come from RBS’s own accounts.

So, not only is the government pumping £25bn of new capital into RBS (as first announced in February). It’s also buying £6bn of new shares in Lloyds Banking Group as part of LBG’s private fund-raising. And it’s creating a contingency rescue fund of £8bn for RBS (which may never be used). Plus the £10bn tax write-off.

That’s close to £50bn of taxpayers’ money.

The Treasury’s defence is a] a lot of the money was announced in the spring, b] RBS will take on more onerous terms such as taking a bigger “first hit” of any losses and c] would your rather let the bank collapse and prompt another financial meltdown?

Even so: These are big numbers. John McFall, chair of the Treasury select committee, told the Commons: “RBS is in a worse state than everyone thought last February.”

A blink-and-you’ll-miss-it moment when John Healey and John Denham were up against the DCLG select committee last night.

The pair denied a recent comment by Richard McCarthy, one of the most senior civil servants at the department. McCarthy (the second highest-paid man in Whitehall, incidentally) had suggested that ministers were not in agreement over Home Information Packs. Of course they insisted that was not true.

McCarthy’s comment struck me as curious. Why would a senior civil servant (they pride themselves on discretion) want to rock the boat?

Time to watch David Cameron squirm explain why he won’t give a referendum to the British public. Expected tomorrow. (A good day to bury bad news as it co-incides with the Kelly report - but expect fireworks at PMQs).

The Czech constitutional court has cleared the Lisbon Treaty, as my colleague in Warsaw reports here.

Klaus - the last man standing between David Cameron and Lisbon’s ratification - could now sign the treaty within a month. Now it’s just a waiting game for Cameron to drop his promised referendum on Lisbon, a pledge which was always going to be difficult to maintain.

Jean Eaglesham writes here that: “David Cameron is poised to rule out a referendum on the Lisbon Treaty….an announcement would come ‘very soon’.”

Cameron won’t give voters a referendum over the Lisbon Treaty, says ConservativeHome

Tory Bear is “raging” over the apparent U-Turn

And Ben Brogan thinks it’s awfully quiet, “too quiet“, out there in Tory-land

The latest erroneous assumption about Tony Blair is that he would enrich himself if he became EU President - an idea put forward in some newspapers in recent weeks.

In fact the likely £250,000 salary for the new post is chicken feed for Mr Blair. It is equivalent to just three speaking engagements. Or to put it another way, it is a twentieth of the fee he is receiving for his memoirs.

Instead, the thrust of our feature last Friday was that the former PM would have to dismantle a large network of business and philanthropic interests if he was to take the new job. In total there are about 80 people working for his various initiatives (which include his Middle East peace role, a sports foundation, an Africa governance initiative and a faith foundation - as well as his commercial advisory business).

We also mentioned that he would have to extricate himself from a generous 10-year lease on his Grosvenor Square office block. There are eight years remaining at £550,000 a year. It is our understanding that the landlord would be very reluctant to let him go without a massive break fee (my guess would be £2m or so). In theory Blair could sub-let: but he would only get about £55 per square foot, much less than the £93 per square foot he is paying at present. (The West End office rental market has slumped).

On that basis, he would still be on the hook for about £250,000 a year of rent - the entire salary of an EU President.