Was it all just a cunning plan?

That, at least, was what some folks in the market found themselves wondering last week when government officials briefed newspapers that all of a sudden the government wasn't going to raise income tax after all.

On the face of it, it looked like yet another shambles in Downing Street, but there was another, intriguing interpretation: that they had actually pulled off something rather extraordinary.

To see why, we need to start a few weeks ago, when the government began energetically briefing that it was considering raising taxes in the forthcoming budget.

This all culminated with that slightly odd press conference at Downing Street, where the chancellor seemed to hint that she was even prepared to abandon the manifesto pledge not to raise income tax.

Here's what happened in that period: the yields on UK government bonds fell. In fact, they fell quite a lot, down from around 4.7% to 4.4%.

Now, appending changes in gilt yields to a single factor is a mug's game - after all, they also reflect things like central bank decisions, not to mention the health of the wider economy.

All the same, it's pretty clear these yields - which feed into the debt interest costs faced by the government, and by extension all of us - are at least somewhat moving as a result of all these government hints and leaks.

We know as much because last Friday, after yet another anonymous government official leaked to a few newspapers that it was no longer planning to raise income tax, the UK 10 year bond yield leapt up sharply.

Anyway, back to the cunning plan, for it also emerged on Friday that the Office for Budget Responsibility had chosen a slightly later-than-usual period as the statistical foundation for its new economic forecasts.

The period it chooses matters because the prevailing interest rates - and currency levels - then feed into its bigger economic models.

Most obviously, higher yields imply higher debt interest costs. Small changes in the yield can have a big impact on the government's budget - by now, perhaps you see where this is going.

Budget 2025: What tax rises could Rachel Reeves announce?

Anyway, it transpires that the period chosen by the OBR was precisely the same period when the government began hinting about its plans to raise taxes. Which in turn raises a question: were all those leaks just a foil to bring down the cost of borrowing?

Because it turns out the main reason the government is no longer planning to raise income taxes (or at least so all those anonymous officials are now briefing) is that the OBR forecasts don't look half as grim as they once did.

Debt interest costs are lower, and, separately, the wage figures that feed into its productivity forecasts look higher.

All of which means the "black hole" Rachel Reeves faces is significantly smaller than previously thought - in large part because of those lower bond yields at precisely the same period the government began briefing about tax rises!

But before we get too carried away here, I should add a massive note of caution.

I strongly suspect this was not a cunning plan. This isn't just based on a hunch or on the assumption that the government would struggle to organise such a cunning plan.

It's based on the fact that most of the government briefing on tax rises happened not during that critical OBR forecast window but after it.

Sure, there were hints dropped during the OBR window - most notably by the chancellor in an interview with my colleague Sam Coates - but that press conference came weeks later.

If this was a cunning plan, it wasn't very well organised. The timing was somewhat off.

Read more on Budget 2025:
Income tax U-turn: What the hell just happened?
How No 10 plunged itself into crisis ahead of budget

Instead, what is far more likely is that, behind the scenes, officials are agonising over something we have all long understood: That the chancellor left herself perilously close to missing her self-imposed fiscal rules in two successive fiscal events and is now reckoning with the consequences.

She gambled and the gamble has not paid off. Most of what you hear about over the next week and a half are the results.

(c) Sky News 2025: Cunning plan or a gamble that didn't pay off? Why some think the chancellor pulle