The state pension is turning into a total mess because of the longstanding freeze on the £12,570 tax-free personal allowance, which, thanks to Rachel Reeves, now runs until April 2031. While the allowance remains frozen, the state pension will keep rising under the triple lock, increasing each year by either consumer price inflation, earnings or 2.5%, whichever is highest. And that’s causing a tax headache for pensioners.

Today, the full new state pension is £12,547 a year, a fraction below the personal allowance. Even it it rises by the 2.5% backstop, the lowest amount possible, it would hit £12,861 next April. That’s £291 more than the personal allowance. It’s likely to even higher, as the Iran war and rising oil price threatens set to push up inflation. Between now and 2031, the state pension will continue to climb ever higher above the personal allowance.

Reeves’s solution to this conundrum was a quick fix. She promised that retirees whose only income comes from the state pension won’t pay income tax during this Parliament. It sounded reassuring, but opened a nasty can of tax worms. The UK has two state pension systems running side by side. Millions who reached state pension age from April 6, 2016, receive the new state pension. If they have absolutely no other taxable income, Reeves’s pledge just about works for them.

But as I explained on Saturday, older retirees are in a different position. They get the basic state pension, worth significantly less, but many also receive additional state pension through SERPS or the state second pension. Those extra payments are taxable. If they push total state pension income above the £12,570 personal allowance, the pensioner becomes liable for income tax on the state pension above that threshold, even if they have no other income at all.

The result? Only one in 20 pensioners will actually benefit from Reeves’s supposed solution. Burnham didn’t create this mess. But he’s inherited it and chosen to push it through. And now there’s a second problem.

Incredibly, Reeves’s quick fix will punish those who did the responsible thing and saved money for retirement, by hitting them with a thumping tax charge. Low income pensioners with just a tiny amount of savings now face a vicious cliff edge. The moment they earn any income from a private pension, savings interest or part-time job, then Reeves and Burnham’s tax-free pledge collapses.

They won’t just pay tax on that extra source of income. They’ll also face tax on the slice of their state pension above the frozen personal allowance.

By 2029-30, analysts at retirement specialists LCP have estimated that the full new state pension could be worth £13,671. That’s £1,101 over the personal allowance. There’s still no tax bill for new state pensioners who have no other sources of income. But it’s a different story for those who do. Just £1 of additional income on top could trigger a punitive tax bill of around £220.

Reeves’s plan created one of the sharpest cliff edges in the entire UK tax system. And now Burnham and new Chancellor John Healey have kicked pensioners over it.

For years, governments urged people to save for retirement and reduce pressure on the state. Reeves has somehow created a system where pensioners who saved modestly could end up worse off than those who saved nothing at all. Now Burnham has made sure it happens.

The new PM has a lot on his plate, and there is no easy solution to the mess Reeves has conjured up. Burnham will hope pensioners don’t notice. But every year the tax thresholds remain frozen, the impact on low income pensioners with modest savings will grow. Reeves set up this disaster. Burnham just applied the finishing touch.