The Chancellor is in a hole. Growth is slowing, inflation is climbing, jobs are vanishing and her black hole has ballooned from £22billion to more than £50billion. She carries most of the blame for this meltdown, as her tax raids on jobs and investment have backfired badly.

With the autumn Budget looming, Reeves is scrambling to find new ways to raise money, and the results could be brutal. Pensions, savings, inheritance and capital gains are all being openly touted as targets.

Having lost control of spending, she dare not confront Labour’s left, so her only route is to raise yet more revenue from already hard-pressed taxpayers. That means nothing is off limits.

Now she’s even considering the unthinkable – scrapping private residence relief. That would be the most dramatic step any Chancellor has taken in modern times.

Most people have never heard of private residence relief. Yet it underpins one of the most basic assumptions of British life, that when you sell your own home, the place you live in, you will not be charged capital gains tax (CGT) on any increase in its value.

If you own a second property, such as a buy-to-let or a holiday home, then the taxman already takes a share when you sell.

Most accept that as fair. There is a clear investment element. But taxing someone’s main home crosses a line that no Chancellor has ever dared step over. They assumed, rightly, it would plunge them and their party into a political abyss.

Nothing would cause more fury than imposing CGT on the sale of family homes. For Reeves even to consider it shows how cornered she has become.

Higher rate taxpayers would pay 24% of any gain they make on their home, while basic rate taxpayers would have to pay 18%, according to a report in The Times. It said this would only apply to homes worth more than £1.5million at first, but another mooted tax would kick in at just £500,000.

Think tank Onward wants Reeves is to impose an annual levy based on a property’s value, to be collected when the home is eventually sold.

It suggested 0.54% a year for homes worth between £500,000 and £1million, rising to 0.81% for anything above that.

These fractions sound small, but they’d roll up year after year, and the cumulative effect would be devastating.

If Reeves acts, this would amount to a revolutionary change in Britain’s tax system. Once the principle of slapping CGT on our main homes has been set, the Treasury will have a field day.

A £500,000 home may sound like a fortune in much of the country, but in London and the South East it barely buys a modest flat.

This will be the thin edge of a long wedge. Once Reeves sets the thresholds, they’ll probably never rise. Thresholds never do these days.

Let’s take just one example. The £325,000 inheritance tax threshold has been frozen since 2009, and that will continue until at least 2030.

If it had kept pace with inflation, it would be worth more than £500,000 by then.

We can expect exactly the same to happen if Reeves abolishes private residence relief. At first, a few wealthier people pay, then slowly, so do the middle classes.

This isn’t just punitive, it’s fiscal madness. The proposed “Mansion Tax” would kill the upper end of the property market overnight, and the destruction would ripple downwards.

Owners would delay selling, hoping the tax would be repealed later. Downsizers won’t take the hit, reducing the supply of family homes. Younger buyers will be wary of purchasing properties well below the threshold, for fear they’ll clobbered one day as prices climb.

I can’t believe Reeves will do this but if she does, Reform and the Tories will have a field day. You can bet your house on that.