In this Britain, the growth plan is given more than seven weeks.
The story everyone agrees on goes like this: a reckless government tried to borrow £45bn for tax cuts, the markets recoiled, pension funds nearly collapsed, and a grown-up had to be sent in to restore order. It is a tidy story. It is also the version written by the people who won, and it skips the part where the fire was out inside a fortnight and the patient was defenestrated anyway.
So run the counterfactual. Same mini-budget, same gilt spike, same frightened Tuesday in the pension system. One change: the parliamentary party does not lose its nerve. Kwarteng is not sacked after 38 days. The 45p climbdown still happens, because that one was always coming, but the growth plan itself is given a year instead of seven weeks. The question this file exists to answer is the one the 49 days made sure nobody could: what was the price of never finding out?
Start with the thing the plan was aimed at, because it is real and it is a scandal in its own right. Britain has spent fifteen years as one of the slowest-growing economies in the rich world. The Resolution Foundation puts the typical British household £8,300 behind its equivalents in Australia, Canada, France, Germany and the Netherlands, and the average worker £10,700 a year worse off in lost pay growth alone. Productivity has grown at roughly half the rate of other advanced economies. Nine million younger workers have never once worked in an economy with sustained rising wages. Match the peer-country average and the typical household would be a quarter richer.
That is the stagnation the 2022 government said, loudly and clumsily, that it wanted to break. It set a formal target of 2.5% trend growth, a rate Britain has not sustained since before the financial crisis. You are allowed to think the method was wrong. What you are not allowed to do is pretend the problem was invented, because the £8,300 is sitting in the national accounts whether or not you liked the messenger.
Then came 23 September 2022. The presentation was indefensible: the package was published without an independent OBR forecast, which the watchdog had offered and which was ready, and it abolished the top rate of tax in the middle of a cost-of-living crisis. That was an unforced error, and this file does not pretend otherwise. But look at what was actually new. Most of the package had already been trailed, the spending on 8 September and the tax measures across the summer, and the new money in it came to around £1bn to £5bn a year, between 0.04 and 0.22 per cent of GDP. The independent consultancy Europe Economics calls that "vastly too small" to explain what markets then did. Sterling still fell to an all-time low of $1.03 against the dollar within days. The sin was in the telling, not in the sums.
What happened next is where the tidy story stops being true.
Gilt yields rose fast. But the thing that turned a bad week into an apparent emergency was not in the Budget at all. It was buried in the pension system, and it had been building there for a decade while the same institutions that later tut-tutted at Truss looked the other way.
The mechanism is called liability-driven investment, or LDI. To match their long-term promises to retirees, defined-benefit pension funds had loaded up on leveraged bets on government bonds. When gilt prices fell, those funds faced collateral calls: post more cash, now, or the positions get closed. To raise the cash, they sold gilts. That pushed prices down further, which triggered more calls, which forced more selling. A doom loop, entirely mechanical, with nothing to do with whether a tax cut was wise. The Work and Pensions Committee later found that "the use of leverage grew in a way that was not visible to the regulators until the crisis hit," and that the Pensions Regulator's own information on LDI was "not sufficiently detailed" to see it coming. The Bank of England's own modelling attributes about two-thirds of the yield spike, a jump of some 103 basis points, to this forced LDI selling rather than to the Budget. The funds faced more than £70bn of collateral calls in a matter of days. Roughly 60 per cent of private-sector final-salary schemes were running these leveraged strategies, and the authorities had examined the risk as far back as 2018 and, in their own words, missed key aspects of it.
Read that twice. The bomb in the basement was a decade of hidden leverage that the regulators admit they could not measure. It was not created on 23 September. It was lit on 23 September, by a spark that could have come from almost anywhere: a rate rise, a global shock, an ordinary bad auction. The pensions plumbing had been rigged to explode on any sharp move in yields, and nobody whose job it was to watch it had noticed. Blaming the mini-budget for the LDI crisis is like blaming the match for the gas leak. The match should not have been struck in that room. But somebody filled the room with gas, and they never faced a voter.
This is where the "unsurvivable" narrative falls apart. On 28 September the Bank of England stepped in to stop the doom loop, exactly as a central bank is meant to. It announced it would buy up to £65bn of gilts, £5bn a day for thirteen days. That £65bn headline is the number that went round the world as proof the country had gone bankrupt.
It never spent it. The Bank bought £19.3bn, less than a third of what it had authorised, and the panic stopped. The 30-year gilt had moved 130 basis points in three trading days, a move the Bank itself called three times larger than any comparable move in its records, and the intervention flattened it. The operation ran for those thirteen days and closed on 14 October. Then, between late November and January, the Bank sold the gilts back to the market, at a profit. The rescue that supposedly proved the plan was insane cost the taxpayer nothing and made money.
The rescue was smaller than the headline that killed her
BANK OF ENGLAND GILT OPERATION, 28 SEP – 14 OCT 2022
SOURCE: BANK OF ENGLAND. THE BANK AUTHORISED UP TO £65BN (£5BN/DAY × 13 DAYS) BUT PURCHASED £19.3BN (£12.1BN CONVENTIONAL + £7.2BN INDEX-LINKED). THE HOLDINGS WERE SOLD BACK TO THE MARKET BETWEEN 29 NOV 2022 AND 12 JAN 2023 AT A PROFIT. UK YIELDS FELL BELOW US YIELDS BY MID-OCTOBER AND BELOW EU YIELDS BY EARLY NOVEMBER; STERLING RECOVERED PAST ITS PRE-BUDGET LEVEL BY MONTH-END. NO PERSISTENT "TRUSS PREMIUM" REMAINED.
There is a detail that makes the rescue stranger still. At the very moment the Bank was buying gilts to halt the LDI spiral, its other hand was reaching for the opposite lever. Days earlier, on 22 September, it had confirmed it would shrink its own gilt pile by £80bn over the coming year, the policy known as quantitative tightening, and it was due to start actively selling gilts into the market in the first week of October. The plan, in other words, was to push extra gilt supply into a market that was already choking on it, which forces yields up, in the same fortnight that a slice of the pension system was being margin-called to death by rising yields. The Bank had to postpone those sales to 1 November precisely because starting them would have poured petrol on the fire it was scrambling to put out. One arm of Threadneedle Street was stamping on the brake while the other revved the accelerator. That is not the signature of a market driven mad by a tax cut. It is the signature of an institution tightening hard into a fragility it had helped build and had never bothered to measure.
So the sequence, stripped of the drama, is this. A real but reckless Budget spooked a market that was already tightening. A hidden fault in the pension system, built over ten years and invisible to its own regulators, turned the spook into a fire. The central bank did its job, put the fire out in under two weeks with a fraction of the firepower it had named, and got the money back. And then, with the emergency already over, the governing party removed its own Chancellor, removed its own Prime Minister, and buried the entire growth agenda with them. The markets did not make the country ungovernable. The party did.
The most durable attack on the 49 days is that Truss put up your mortgage. It is the line everyone remembers, and the data does not carry it. Look at the average rate on newly issued mortgages and there is no Truss-shaped step in September or October 2022. Rates rose because the Bank of England was raising its own rate to fight inflation, the same climb happening right across the rich world, and the one clear jump in the series lands in late summer 2023, nearly a year later and nothing to do with the mini-budget. Fixed-rate deals were pulled and repriced for a fortnight during the panic, which was real and frightening for anyone remortgaging that month. But the lasting mortgage pain that got hung around her neck was the interest-rate cycle, and it was coming for whoever stood in Downing Street.
No vibes. Here is exactly what we did, and what we deliberately did not do.
ASSUMPTIONS, IN PLAIN ENGLISH
- What the counterfactual changes: the party holds firm, the growth plan survives past seven weeks, and Britain reaches for the 2.5% trend growth rate the 2022 government actually set as its target. We are not modelling every policy. We are modelling the gap between the growth Britain settled for and the growth it aimed at.
- The base: UK GDP of roughly £2.56 trillion across about 28.4 million households, so approximately £90,000 of national income generated per household each year. This is national income, GDP, not your payslip. We say so plainly because it matters (see the honesty section).
- The two paths: the actual trend, taken as about 1.3% a year, roughly Britain's recent record; and the growth-plan trend of 2.5% a year, the target itself. We compound both from 2022 and read off the gap in 2030, eight years out.
- The whole thing rests on one contested "if": that the plan would have delivered the growth it targeted. It might not have. No government since 2007 has hit 2.5%. The calculator lets you set that rate yourself, because it is the argument, not a fact we are smuggling in.
- Static model. No feedback from interest rates, no distributional split, no second-round effects. Household aggregate uses about 28.4 million GB households. Sources listed at the foot.
Three numbers frame the whole affair. How long the plan lived, what its "unsurvivable" crisis actually cost, and where the tax burden went the moment the cuts were reversed.
That third number is the reckoning for everyone who cheered the plan's death as fiscal responsibility. Britain did not get lower taxes and it did not get prudence. It got the highest tax burden since the 1940s, delivered not by an honest rise in the rates but by freezing the thresholds and letting inflation drag people into bands they were never meant to reach. The stealth tax that replaced the growth plan is larger than the growth plan was, and no market has ever staged a run against it, because it never had to be announced.
What was announced on 23 September, and what actually survived the reversal. The reddened rows are the ones that were killed.
| MEASURE (23 SEP 2022) | VALUE | FATE |
|---|---|---|
| Basic rate of income tax, 20% to 19% | up to £377/yr | Scrapped |
| 45p additional rate abolished | top earners | Reversed 3 Oct |
| Corporation tax frozen at 19% | vs 25% | Reversed 14 Oct |
| IR35 contractor reforms repealed | self-employed | Reversed 17 Oct |
| National Insurance 1.25% levy reversed | ~£330/yr avg | Kept |
| Stamp duty threshold raised | up to £2,500 | Kept |
Notice what survived. The two measures the incoming Chancellor kept, the National Insurance reversal and the stamp duty cut, were among the largest in the package. The government that "restored credibility by reversing the mini-budget" held on to a good chunk of it. What it threw overboard was the growth-facing half: the income tax cut, the investment signal, the bet on making Britain a place capital wanted to be. The prudent, unglamorous bits stayed. The ambition is what got reversed.
Set the trend growth rate you think the plan could have delivered. This is the honest way to argue a counterfactual: you supply the contested number, and the arithmetic does the rest. It shows the extra national income per household by 2030, against Britain's actual recent trend of about 1.3% a year.
NATIONAL INCOME (GDP) PER HOUSEHOLD, NOT TAKE-HOME PAY. BASE ≈ £90,000/HOUSEHOLD (UK GDP ≈ £2.56TN ÷ ≈28.4M HOUSEHOLDS). BOTH PATHS COMPOUNDED FROM 2022 TO 2030. ACTUAL TREND FIXED AT 1.3%/YR. THE PLAN DELIVERING ITS TARGET IS AN ASSUMPTION, NOT A FACT.
(CONDITIONAL ON THE PLAN DELIVERING 2.5% TREND GROWTH, WHICH IS PRECISELY WHAT ITS CRITICS DENY)
That £280bn is bigger than the entire NHS budget, and it is the polite version, because it assumes the plan hit its target cleanly and nothing else changed. Dial the calculator down to 2% and the gap is smaller but still enormous. The point is not the exact figure. The point is that the cost of fifteen years of stagnation is measured in hundreds of billions a year, and Britain's response to a government that tried, however badly, to do something about it was to end that government in seven weeks and return to managing the decline.
This is where a partisan file would take a victory lap. Three things are true at once, and any version that gives you only one of them is selling you something.
First, the target was right even if the messenger was doomed. Britain's stagnation is not a talking point, it is £8,300 a household and fifteen lost years, and a country that treats every attempt to break it as an outrage will keep the stagnation. Something was worth trying. That much the numbers settle.
Second, the launch was reckless, and this file will not pretend otherwise. Publishing the package with no OBR forecast, abolishing the top rate during a cost-of-living crisis, into the teeth of a global tightening cycle, was an act of self-harm, however small the new borrowing turned out to be. The strong claim, that the Bank of England engineered the crisis to bring the government down, still goes beyond the evidence: the Bank stopped a fire it did not light, even as its own bond-selling plans were adding to the heat. The honest middle, and it is backed by the Bank's own numbers and by independent analysis, is that the Budget was the spark and a decade of hidden pension leverage was the fuel. A government that hands its enemies a spark in a room full of petrol does not get to be surprised by the fire.
Third, and this is the uncomfortable one, both of those can be true and the establishment story still be a cover. The LDI bomb was real, hidden, and not the government's creation. It was assembled over a decade by pension funds and waved through by regulators who admit they could not even see it, and it would have gone off on some other shock sooner or later. So "she lit the fuse" and "the building was already soaked in petrol by people who never stood for election" are both true. The scandal that got a name and a sacking was 49 days long. The scandal that kept its job was ten years in the making, and it is still there, in the plumbing, waiting for the next match.
Put those together and the counterfactual is precise, not triumphant. A Britain that backed the plan would not have escaped the reckless launch, the market fright or the 45p climbdown. What it would have escaped is the decision to kill the entire growth agenda for a fire that was already out, and to answer a decade of failure with a return to the exact managed decline that produced it.
Britain did not reject Trussonomics after a fair trial. It never held one. The plan was launched badly, ambushed by a fault nobody had bothered to fix, rescued in under a fortnight at no cost, and then destroyed by its own side while the rescue was still working. What replaced it was not prudence. It was the highest tax burden since the war, arriving by stealth, on top of the same stagnation the plan was meant to end.
And the crash itself? The independent review by Europe Economics is blunt about it. Economic output did not fall, or even slow relative to what had been expected. In the quarter after the mini-budget, GDP grew faster than it had in some time, a quarter the Bank had forecast would open a long contraction. Unemployment stayed at historic lows. There was no sustained loss of wealth. In the report's words, the economy "did not crash, by any understanding of an economic crash that economists would normally recognise." The country was told it had watched a catastrophe. What it had actually watched was a fortnight of bond-market turbulence, a competent central-bank rescue that turned a profit, and a governing party losing its nerve.
You do not have to think Liz Truss was right to think the country learned exactly the wrong lesson. The lesson taken was that ambition is dangerous and the safe move is to manage the decline politely. The lesson available was that Britain has a pension system rigged to detonate, regulators who could not see it, and a growth problem worth hundreds of billions a year that it keeps refusing to treat. One of those lessons costs nothing to ignore. The other one is on the invoice, every year, and it never stops printing.
The markets did not end the shortest premiership in British history. The party did, while the fire was already out. Britain called that prudence, went back to the slowest growth in the rich world, and quietly raised taxes to the highest level since the war. The bill for losing your nerve does not arrive in a headline. It arrives in fifteen years you never notice passing.
- The 23 September 2022 mini-budget: ~£45bn/yr of tax cuts (~£161bn over five years) plus a ~£60bn energy package, published without an OBR forecast; sterling fell to an all-time low of $1.0327 on 26 September. Reversal timeline via the House of Commons Library, 17 October 2022 fiscal statement: 45p abolition reversed 3 Oct, corporation tax and basic-rate cut reversed, IR35 and VAT-free shopping reversed; NI reversal and stamp duty change retained.
- Bank of England, gilt market case study (2023): intervention announced 28 September, up to £65bn authorised (£5bn/day × 13 days); £19.3bn actually purchased (£12.1bn conventional + £7.2bn index-linked); 30-year gilt yields rose 130bps in three trading days, "three times larger than any other historical move over a similar period"; holdings sold back 29 Nov 2022–12 Jan 2023.
- Bank of England, An anatomy of the 2022 gilt market crisis (Staff Working Paper 1,019): the LDI collateral-call doom loop and the mechanics of forced gilt selling.
- Bank of England, quantitative tightening and APF gilt sales (Sep–Oct 2022): the MPC confirmed on 22 September 2022 an £80bn reduction in the gilt stock over twelve months, including active sales due to begin in early October; the start of active gilt sales was postponed to 1 November 2022 during the LDI intervention.
- Work and Pensions Committee, Defined benefit pensions with LDI: leveraged LDI "grew in a way that was not visible to the regulators until the crisis hit in September"; "gaps in the arrangements for managing systemic risk"; the Pensions Regulator's LDI information was "not sufficiently detailed" for oversight.
- Resolution Foundation, Ending Stagnation / Economy 2030: typical UK household £8,300 behind peers (Australia, Canada, France, Germany, Netherlands); average worker £10,700/yr worse off in lost pay growth; productivity growth roughly half the advanced-economy rate; nine million younger workers have never known sustained wage rises; the typical household would be ~25% better off matching peers.
- Office for Budget Responsibility, the UK tax burden in context: tax as a share of GDP forecast to reach a post-war high of 37.7% in 2027-28, driven substantially by frozen thresholds (fiscal drag). Fiscal-drag mechanics in the House of Commons Library explainer.
- The 2.5% trend growth target: set as the explicit objective of the 2022 growth plan, a rate the UK has not sustained since before the 2008 financial crisis.
- Europe Economics, "Did Liz Truss Crash the Economy?" (January 2025): the new fiscal measures totalled only ~£1bn–£5bn/yr (0.04–0.22% of GDP), "vastly too small" to explain the market moves; the Bank's modelling attributes about two-thirds of the ~103bps yield spike to LDI forced-selling; LDI funds faced >£70bn of collateral calls; ~60% of private-sector DB schemes used LDI; the authorities examined the risk in 2018 but "missed key aspects"; UK yields fell below US yields by mid-October and below EU yields by early November, with no persistent "Truss premium"; average new-mortgage rates showed no Sep/Oct 2022 dislocation; and "the economy did not crash, by any understanding of an economic crash that economists would normally recognise."
- Portrait: official portrait of Prime Minister Liz Truss, 24 September 2022, by Simon Dawson / No 10 Downing Street, via gov.uk. Contains public sector information licensed under the Open Government Licence v3.0.
- Full model: national income (GDP) of ≈ £2.56tn across ≈ 28.4m households ≈ £90,000/household; the actual path compounded at 1.3%/yr and the counterfactual at the user-set rate (default 2.5%), both from 2022 to 2030; the gap read off in 2030 and aggregated across households. A deliberately static model with no interest-rate, behavioural or distributional feedback. The counterfactual growth rate is set by the reader because it is the contested assumption, not a settled fact.