Rachel Reeves will be hoping this Budget buys her some time

Finally, after weeks - even months - of hearing about it, we are about to find out what is actually in this year's Budget.

Chancellor Rachel Reeves will make an argument about what she will call "the fair and necessary choices" she is taking.

Necessary is code for difficult.

The thrust of the Chancellor's address will be three cuts – cutting the cost of living, cutting NHS waiting lists and cutting government debt, as a proportion of national income.

Making that happen will involve taxes going in the other direction – and the snag is putting up taxes increases the cost of living for those with higher tax bills.

Reeves will argue there will be plenty in there, such as freezing some rail fares, that will help address the cost of living for some.

The snag of not putting up income tax rates means a flotilla of other smaller tax rises on particular groups of people, which could lead to noisy, coordinated protest of the kind we saw from many farmers after last year's announcement about their inheritance taxes.

Every year there is the faintly absurd recipe of a dollop of briefing, several tablespoons of speculation and a sprinkling of leaks.

But this year has been something else: a Budget in the last gasps of autumn has meant all of the above has been served up, with ever increasing frequency, since the kids were still on their summer holidays.

On top of all that, the Chancellor herself has chosen to join the pre Budget public conversation more often than has ever happened before.

There is an underlying reason for all of this: Rachel Reeves, the prime minister and the rest of the government have long known this is a landmark moment for them.

Opinion polls suggest this still relatively new government is deeply, deeply unpopular, and the prime minister and Chancellor even more so.

The economy continues to stutter, the cost of living continues to bite for millions, and ministers from the prime minister down acknowledge that the promise of "change" they were elected on isn't coming remotely fast enough for many people.

Against that backdrop, Labour MPs are increasingly restless. They can feel the party's current unpopularity in their bones, in their inboxes and in their conversations with their constituents.

"This is the middle of the end," one tells me, anticipating that this will be Sir Keir Starmer's and Reeves's last Budget.

"I am on a four-year walk to the guillotine," says another, anticipating defeat at the next general election.

Even the most loyal, the least likely to want to sound negative end up sounding just that privately.

Little wonder that Reeves has had to say out loud that she looks forward to next year's Budget and the one after that - chancellors only ever have to do this when some think that is rather unlikely.

I struggle to find any Labour MPs who will privately attempt to argue the weeks leading up to this Budget have been anything other than a mess.

It has been sufficiently messy that it has prompted some to argue the very idea of an annual Budget should be scrapped entirely.

The relationship between the government and its backbenchers is at best tetchy, at its worst volcanic.

Deep unpopularity in the country and jittery Labour MPs is the prism through which both the countdown to this Budget and its aftermath should be seen.

The prospect of it going down so badly there was a leadership challenge, possibly before Christmas, is what prompted some of those loyal to the prime minister to tell some reporters Sir Keir would fight any such challenge.

The prospect of mutiny among Labour MPs if the Chancellor had smashed Labour's manifesto promise not to put up income tax rates prompted both the attempt a few weeks ago to make the case for it, and the decision a week or so later to have second thoughts.

Wobbly indecision in plain sight is near impossible for Labour MPs to defend.

But the lack of warmth cuts both ways.

"The Parliamentary Labour Party is sprawling and naïve," one government figure tells me.

"They want to avoid the trade-offs and we have to tell them we're in government, you can't do that."

The best Rachel Reeves can hope for is that this is a Budget she can get through without making her and Sir Keir Starmer's parlous situation even worse – and that it buys them some time, and some patience, from their own MPs and the country.

But they both know there isn't much patience about.

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