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Labour is crying foul this morning.

The Shadow Chancellor John McDonnell says he's angry the Conservatives haven't given out full costings for their manifesto.

Labour of course, did show us their sums at their launch earlier in the week, and they are on the warpath.

The Tories are vulnerable to claims their plans would hit millions of people, because they will not give out the details of how their plans would actually work.

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On the winter fuel allowance, for example, experts like the Resolution Foundation believe the only realistic way to introduce means testing is to limit the benefit to pensioners who get pensions credit.

To do otherwise would be an administrative palaver, would create costs and would only give limited savings.

But use that system, and five out of six pensioners would lose out, which translates to 10 million people - yes, you read that right, 10 million.

In that scenario, only people entitled to pension credit would keep the benefit - those with a family income of less than £159.35 a week if they're on their own, or £243.45 for couples.

Open to suspicions

Tory sources suggest that is not the intention at all, that they will create a new means test instead, implying that the numbers won't be as large.

But they won't give any more detail than that; the plan is instead to produce a draft version of the new rules, a Green Paper, if they win, and then consult on the best way to do it.

Without being specific of course, they do leave themselves open to suspicions about their true intentions.

The same is true on their plans for social care.

How many more people will be asked to pay? How exactly will the proposed system work? They are making big promises but again the plan is to produce a Green Paper if they win, then work it out.

Again, on immigration there are questions about detail - ministers won't put a timetable on when they think they will actually (finally) get net migration down to the tens of thousands.

It is not unusual not to produce detailed breakdowns of every policy cost in manifestos.

They are broad contracts with the electorate, and no politician wants to set themselves too many tests that are impossible to pass later.

Labour is often under more pressure to show their numbers because, traditionally, they are considered to be behind on economic credibility.

I remember the Greens, too, in the last election, going to huge efforts to show they were a serious force to be reckoned with by publishing their numbers and an independent audit alongside.

That didn't save Natalie Bennett, the then leader, from quite an awkward moment when we asked her how she planned to spend one billion pounds on 'The Earth', as their spreadsheet suggested.

But some of Theresa May's plans have plenty of blanks to be filled in.

And if the Tories won't, then others will and questions will keep being posed.

Guessing will go on

Just as George Osborne was asked again, and again, and again, in the last election about how on earth he would make £12bn of welfare cuts, the Tories will keep getting asked this time round exactly what their plans will be.

This morning, David Davis said that numbers doing the rounds this morning were just "guesswork". But that is exactly the issue - for as long as they don't give the full details, the guessing will go on.

PS: On where the numbers end up on winter fuel allowance, if the Tories win, one of the most interesting things is that Theresa May would be dipping her toe in challenging the gap between young and old.

In the last few years, pensioner incomes have been continually protected, many would argue at the expense of the younger generation.

Part of this manifesto seeks to start to reverse that, which is a fundamental shift.

The former Treasury adviser and well respected policy wonk Torsten Bell has explored that a bit here.

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