Truss and Kwarteng unveil September 2022 Growth Plan tax cuts without OBR forecast

Decision and public stakes

On 23 September 2022 Chancellor Kwasi Kwarteng presented The Growth Plan 2022 for Prime Minister Liz Truss's government. It proposed a large package of tax reductions and supply-side reforms while retaining energy-support commitments. Its central political bet was that lowering tax rates and promising deregulation would change incentives enough to accelerate long-term growth. That is a defensible policy hypothesis, but it is not an observed growth outcome. The announcement was not accompanied by an updated Office for Budget Responsibility economic and fiscal forecast. That omission mattered because a large change in the fiscal outlook was being announced while gilt investors, mortgage lenders and households faced unusually high inflation and rapidly changing interest-rate expectations.

Policy instrument and fiscal mechanism

The official Treasury document targeted a 2.5 per cent trend growth rate. It proposed cancelling the planned increase in corporation tax from 19 to 25 per cent, bringing the basic income-tax rate reduction to 19 per cent forward to April 2023, and abolishing the additional 45 per cent income-tax rate. These had different distributional consequences: a change to corporation tax principally affects profitable companies and investment incentives; the additional-rate proposal concentrated its direct statutory benefit among the highest earners; a one-percentage-point basic-rate cut would have covered a much wider taxpaying population. The package also reversed the recent National Insurance rate increase. Its announced growth target was not an independently verified forecast of what would result.

Decision authority and implementation

The stamp-duty thresholds changed immediately in England and Northern Ireland. The residential nil-rate threshold rose from £125,000 to £250,000, while the first-time-buyer threshold increased from £300,000 to £425,000 and the maximum qualifying property value from £500,000 to £625,000. These were operative tax measures rather than mere aspirations. Their consequences were also ambiguous: buyers able to transact could reduce transaction tax, but sellers could capture part of the benefit if scarcity and competition raised offered prices. Devolved property taxation meant the specific stamp-duty changes did not simply apply identically throughout the UK.

Money and affected groups

Formal decision-making was split across the Treasury, ministers, Parliament and independent institutions. The Chancellor could announce the tax plan and direct Treasury policy, but proposed income-tax and corporation-tax changes required the relevant legislative steps. Parliament retained authority to enact or reject those provisions. The OBR was not a vetoing body; it was the institution normally tasked with independently scrutinising forecasts and costing the government's policy choices. The Bank of England was separately responsible for monetary-policy decisions and financial stability, not for deciding the government's tax preferences.

Independent scrutiny and legal stage

The fiscal trade-off was immediate. Lower taxes reduce receipts relative to the policy baseline unless offset by sufficiently higher taxable activity or reduced spending. Whether a particular tax cut eventually improves receipts depends on behavioural responses, the tax base and the time horizon. The Treasury's September provisional costings relied on earlier forecast assumptions, with final costings postponed to a later forecast. It would therefore be wrong to present the publicized tax package as already self-financing or to treat every pound of projected fiscal cost as a cash payment to a particular corporation.

Main competing explanation

Supporters expected business confidence, investment and work incentives to improve and argued that sluggish productivity justified a break with previous policy. The strongest contrary argument was not that tax incentives never matter. It was that a rapid fiscal loosening without a contemporaneous independent forecast reduced the credibility of borrowing plans while inflation was already forcing monetary tightening. Bond markets price the state's financing needs, inflation risk and the credibility of future policy; global yields also moved at the same time. Not every basis point of yield movement can be attributed exclusively to this announcement.

Market and public-service consequences

The immediate market crisis developed in the following days, and the Bank of England intervened in long-dated gilts on 28 September after forced-selling pressures linked to pension investment strategies. That sequence is crucial for interpreting this dated fact, but the Bank's action is an independent later event. The Growth Plan itself neither instructed the Bank to buy bonds nor legally committed the government to guarantee every pension investment portfolio. Subsequent reversals also mean that the September proposals should not be counted as tax reductions that all remained in force for years.

Who benefits and who pays

For households, the welfare transmission ran through tax liabilities, borrowing costs, house purchase costs and public-service financing. A potential lower income-tax bill could coexist with a higher mortgage quotation, and a nominal tax saving could be eroded by inflation. These are mechanisms, not an identified national household loss attributable to one document. The relevant measurable indicators are public debt relative to GDP, price inflation, housing costs and interest rates, interpreted alongside global economic conditions.

Indicators and what to monitor

The subsequent cancellation of central proposed income-tax and corporation-tax measures showed that a Budget announcement is not equivalent to durable legislation. The 17 November Autumn Statement expressly said that reversals of most Growth Plan measures plus retention of the 20 per cent basic rate would raise an estimated £34 billion annually against that plan. That comparison is a government estimate of policy change, not a retrospective measure of how much money the September announcement itself transferred. The September decision remains a useful opening event for a driver tracing trust in fiscal rules and institutions.

Limits and historical significance

The fair test of the Growth Plan is therefore threefold: identify exactly which measures commenced; compare forecasts and borrowing rates against the contemporaneous wider market; and distinguish anticipated growth from realized productivity. Direct beneficiaries of the stamp-duty change can be described by eligibility, but broader claims about a national investment boom or permanent fiscal damage require longer-run evidence. The central documented fact is a large, politically consequential fiscal announcement made without the usual same-day OBR assessment. That institutional choice helped define the next phase of Britain's public-finance debate.

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