Brits will lose £2 in "stealthy" freezes for every £1 gained through Liz Truss's tax cuts, a respected think tank has warned.
Analysis by the Institute for Fiscal Studies (IFS) found households will lose more over the next three years than they will gain from Tory cuts to personal taxes.
The Prime Minister's mini-Budget - which spooked markets and triggered days of economic turmoil - included reductions in national insurance contributions (NICs) and the 1p cut to the basic rate of income tax.
Ms Truss and her Chancellor Kwasi Kwarteng have already been forced into a U-turn over their disastrous decision to abolish the 45p top rate of income tax for the richest Brits.
Labour called for the PM to "reverse the disastrous Budget now".
The IFS found that the remaining cuts come during a four-year freeze to income tax thresholds, and many other tax and benefit thresholds and values are also frozen indefinitely.
As a result of the four-year freeze to the personal allowance, by 2025-26 the number of income tax payers will rise to 35.4 million (66% of adults) - 1.4 million more than the current number (34 million, 63% of adults), according to the projections.
Image:
REUTERS)The four-year freeze to the higher-rate threshold also means that by 2025-26, 7.7 million people will be paying higher-rate tax (14% of adults) - the highest rate on record - and 1.6 million more than the figure currently (6.1 million, 11% of adults), the IFS added.
After the U-turn on the 45p tax rate, by 2025-26 there are projected to be around three times as many additional-rate income tax payers as there were when the rate was introduced (760,000 versus 240,000).
The IFS also said there are various aspects of the benefits system where freezes are biting.
Around half a million more families are projected to lose some or all of their child benefit entitlement by 2025-26 compared with now, taking the total to 2.5 million (31% of families with children), because the £50,000 threshold at which child benefit starts to be tapered away has been frozen since its introduction in 2013.
Tom Wernham, a research economist at IFS and an author of the report, said: "Of all the changes to taxes and benefits over the next three years, freezes to various tax and benefit thresholds and allowances are the most significant and least transparent.
"Freezes far more than outweigh headline policies such as the 1p cut to the basic rate of income tax, or the reversal of the health and social care levy, and they are set to drag millions more into the tax system and into higher rates of tax.
"Giving with one hand and taking with the other in this way is opaque and stealthy - and when inflation is volatile the impact can vary hugely from what the Government initially intended.
Image:
Getty Images)"For example, the unexpected bout of inflation we're now facing means that the freeze to income tax thresholds is around four times as big a tax rise as expected when the policy was announced."
The analysis focused on changes in benefits and taxes on personal incomes and did not incorporate recently announced cuts to corporation tax or stamp duty.
The IFS also only considered changes to the tax and benefits system set to still in place in 2025-26, and did not incorporate the energy price guarantee, one-off cost-of-living grants or the 5p cut in fuel duty.
Tom Waters, a senior research economist at the IFS and another author of the report, said: "Practically every part of the tax and benefit system contains allowances, amounts or thresholds that are frozen, often indefinitely.
"Some are farcical - the Christmas bonus, paid to pensioners and disability benefit recipients, has been frozen at £10 since 1977, in which time prices have more than quintupled."
Alex Beer, welfare programme head at the Nuffield Foundation, said: "Frozen tax and benefit thresholds do not account for changes in the cost of living and as a result can fail to reflect household needs.
"One example is the benefit cap, where the threshold freeze dramatically increases the numbers of families subject to the cap and reduces the amount of real support the benefit system offers.
"Evidence shows that parents currently subject to the cap struggle to meet their children's basic needs, and that it increases maternal mental ill-health and risks affecting children's emotional and physical development."
Shadow Treasury Minister Tulip Siddiq said: "The Tories' failed trickle-down economics is hitting people's pockets.
" Liz Truss must reverse her government's disastrous budget now."
A Treasury spokesperson said: "This Government is committed to a high growth and low tax economy and helping people to keep more of their hard-earned money is a key priority, as seen by our commitments to cancel the rise in national insurance and reduce the basic rate of income tax.
"The income tax system is highly progressive. This year, the top 50% of income taxpayers are expected to pay around 92% of total income tax while the bottom 25% are expected to pay just 2%."