Earlier this year, it emerged that Reeves is thinking about slashing the £20,000 Cash ISA allowance, possibly to as little as just £4,000.

It's being spun as a move to boost the economy, encouraging more people to invest in UK companies via Stocks and Shares ISAs. In practice, this would be a punitive tax raid on the elderly and cautious savers who prefer the safety of cash over risking their money on the markets.

Whatever the Chancellor's motives, savers aren't hanging around. Savings platforms are reporting a rush of people pouring money into Cash ISAs.

The annual £20,000 ISA allowance has always been issued on a "use it or lose it" basis, but this time it's different. Savers risk losing it for good. Or at least, the vast majority of it.

Financial experts - me included - have been urging savers to max out their Cash ISA allowance while they still can. It seems they don't need much encouragement.

New figures from Hargreaves Lansdown show record inflows in the first 20 days of the new financial year.

Mark Hicks, head of active savings, says HL's Cash ISA offerings are "booming" - and it's largely down to Reeves.

Savers are desperate to shelter as much money as possible before Reeves wields the axe next April.

They're also desperate to protect their wealth from her freeze on income tax thresholds.

The freeze runs until at least 2028 and will push more savers into higher tax brackets, leaving them more paying income tax on interest earned outside an ISA.

A third factor is fuelling the frenzy.

Reeves has picked a terrible moment to encourage more investment in Stocks and Shares ISAs, just as global stock markets crash thanks to Donald Trump.

No wonder so many are seeking the safety of cash. Frankly, who can blame them?

Some brave souls will view today's falling markets as a buying opportunity. But I fully understand why others want nothing to do with it.

Those who want to lock in a decent savings rate shouldn't hang around. D-Day is looming.

With the global economy teetering, the Bank of England (BoE) is under pressure to slash interest rates to support growth. Markets reckon there's a 100% chance the BoE's Monetary Policy Committee will cut bank rate at its next meeting.

Its most likely move is a 0.25% cut, taking today's 4.5% rate down to 4.25%. There's also an outside chance of a bigger 0.5% cut to 4%.

Either way, the impact will be the same: best buy savings rates will plunge if the BoE cuts. That's yet another reason why Cash ISA savers are getting their skates on.

Hargreaves Lansdown reports that the proportion of deposits going into fixed-term Cash ISAs jumped fourfold in April.

Hicks said it's possible to get as much as 4.5% today but with three more BoE rate cuts likely in 2025 today's best buy deals won't last. "Savers who can afford to lock their money away should grab them quickly before they disappear."

One and two-year fixed terms are proving most popular. However, savers should consider fixing for longer if they can afford to tuck their money away.

Shawbrook Bank is currently offering a market-leading 4.12% a year on its five-year fixed-rate bond, while Chetwood Bank pays 4.05% via HL Active Savings. Leeds Building Society pays 4% over the same term.

If the BoE cuts rates on D-Day, then follows up with more reductions, similar rates could soon be way out of reach.

Of course, there's a slim chance base rates could rise again if inflation spikes. But right now, that seems the less likely outcome.

Time is running out to beat Rachel Reeves. So consider making full use of your £20k Cash ISA allowance, while you still can, and while rates are relatively high.