Reeves will need her hard hat for the next 12 weeks

It is going to be a long 12 weeks, critical to the chancellor, the government and the nation’s economy.

Rachel Reeves chose to talk to me at a Birmingham housebuilding development to launch the Budget process as she tried her hand at some bricklaying.

However, the obligatory hard hat might come in rather handy away from the site as the chancellor wanted to get across that the point of her Budget would not just be to “raise enough money” for public services – which is code for tax rises.

She wants to be known as a reforming chancellor who made much-needed structural reforms to how the tax system operates, in a bid to boost economic productivity and growth to improve living standards.

First and foremost, that requires a reassertion that she is in charge of this process.

“I will make the decisions,” she said, “in lockstep” with Number 10.

That statement is in a week of economist transfers where the Treasury has become something of a feeder club to Number 10.

Off the junior ministers’ bench has been Darren Jones, Reeves’ former deputy, who has taken up a newly-created role as Chief Secretary to the Prime Minister.

Football analogies aside, the immediate challenge facing Reeves is the size of the gap in the public finances.

The chancellor chose to dismiss the suggestion of a “£50bn black hole”, and talk of a need for a visit to the International Monetary Fund to request a bailout.

She also savaged some of the Budget speculation over tax rises on property, banks and pensions as not just “wrong” but “irresponsible”.

The Treasury says it has not been flying kites over the summer.

I also put to her the very interesting words of the Office for Budget Responsibility (OBR) in July, on levelling with the public that “promises made are constantly not kept” on tax and spending.

There was the mildest air of annoyance with the forecaster whose analyses are so critical to the Budget process.

“The OBR have got an important job to do and their job is to produce four forecasts on the economy – not to give a running commentary on government policy,” she replied.

While the chancellor has been a massive supporter of the OBR, granting it more independence, this nerdy point could reflect some looming tension over its assessment of her economic policies.

Expect some considerable haggling with the OBR from the freshly recruited array of high-powered Downing Street economists.

Reeves will stick to her fiscal rules around borrowing, she says.

But there will be pressure from her backbenchers to fudge them.

What spending reductions could be on the cards? Well, the chancellor did not rule out welfare cuts, even after the remarkable U-turn on disability benefits in July.

She may also be a hostage to fortune in the promise that the Budget will help bring inflation, currently at 3.8%, down.

Many typical measures aimed to raise revenue push it up, and that was the experience last year.

Even as she was asserting control over this crucial Budget process, the bond markets reminded her that they can be just as powerful.

She may well find the message useful in managing her own internal scrappy politics.

It’s going to be a rough ride to 26 November.