A recent policy booklet published by the UK’s opposition Conservative Party features a prominent financial figure regarding the "cost of net-zero" that appears to have been inflated twofold due to a fundamental spreadsheet calculation error.
The policy document, titled "The Right Way" and framed as a "common sense" guide for the party, argues that what citizens ultimately desire is a government competent enough to solve the practical problems for which it takes responsibility. Within its pages, a specific section cautions that sophisticated economic modelling should never serve as a substitute for grounded political judgment, leading the authors to challenge and disparage various prevailing estimates concerning the national cost of transitioning to a net-zero carbon economy.
However, in building its argument, the Conservative publication asserts—incorrectly—that the UK government’s official independent adviser, the Climate Change Committee (CCC), had previously placed the total cost of achieving net-zero at close to £1 trillion. Specifically, the booklet claims that in 2020, the CCC estimated its proposed route to net-zero would cost £957bn.
In reality, the CCC’s official 2020 estimate was exactly half that stated amount, standing at £478bn. Furthermore, the committee updated its projections last year, publishing a significantly revised net figure of £108bn, a reduction largely driven by the rapidly falling costs associated with electric vehicles and low-carbon technologies.
Spreadsheet Error
The root of the Conservative Party’s erroneous claim traces back to a technical misinterpretation of supporting data found within a spreadsheet published by the CCC alongside its Sixth Carbon Budget advice in December 2020.
That 2020 spreadsheet contained a comprehensive table detailing the additional capital investments required to construct a net-zero economy over a thirty-year horizon spanning from 2020 to 2050. These projected capital expenditures, categorized as "CAPEX," covered everything from low-carbon electricity generation infrastructure to domestic heat pumps and electric vehicles.
According to the data, these extra capital investments added up to a total of £1.38tn over the three decades. When weighed against anticipated operational savings, categorized as "OPEX," which were calculated at £0.90tn over the same period, the combined net accounting of CAPEX and OPEX figures for 2020 to 2050 yielded a total net cost of £478bn.
The confusion appears to have arisen because the CCC spreadsheet featured both annual sectoral figures and a separate summary row providing combined annual totals for each individual year. An independent review of the data trail indicates that an analyst mistakenly added all of these numbers together from top to bottom, inadvertently counting the underlying costs and savings twice.
This double-counting error inflated the true net cost of net-zero from £478bn to £957bn. This doubled figure is precisely what found its way into the Conservative Party’s official policy booklet.
When the CCC originally published its findings in 2020, it emphasized that the true £478bn net cost amounted to less than 1% of the United Kingdom’s gross domestic product (GDP) spread across the entire 30-year timeframe. The committee pointed out at the time that the massive capital outlays required would not only generate substantial savings by cutting costly fossil fuel imports, but would also provide an overall net boost to national GDP of around 2%.
Subsequent updates by the committee have underscored this trajectory. In 2025, the CCC revised its investment cost and operating savings projections to £670bn and £562bn respectively, resulting in a revised net total of £108bn over the 2025 to 2050 period—representing less than 0.2% of GDP. Earlier this year, the committee reiterated that successfully cutting emissions to net-zero would ultimately cost the UK economy less than a single typical fossil fuel price shock, while delivering ongoing benefits valued at approximately £110bn annually.
Paper Trail
While the Conservative Party document formally cites the CCC’s 2020 advice on the UK’s sixth carbon budget as its source, the official budget documents do not contain the £957bn figure.
Investigative tracing reveals that the earliest online appearance of the £957bn figure occurred in a January 2026 article published by The Spectator, authored by retired engineer and self-described "accidental energy analyst" David Turver. Just a day after that article appeared, Turver repeated the mistaken figure in a formal report published by the free-market think tank, the Institute of Economic Affairs, explicitly citing Figure 5.3 of the CCC’s 2020 supporting data.
Because the underlying spreadsheet for Figure 5.3 totals only £478bn, experts analyzing the paper trail concluded that Turver had mistakenly summed every single data line in the spreadsheet, failing to account for the pre-calculated annual totals and thereby duplicating the figures.
Turver’s initial report also generated a broader ripple effect across various media outlets and commentary circles, sparking inaccurate headlines claiming that net-zero would cost anywhere from £7.6tn to as much as £9tn. Those even higher figures relied on implicit assumptions that essential infrastructure—including fossil fuels, cars, home heating boilers, and power plants—would essentially operate at zero cost.
Following the circulation of Turver’s report and article in early 2026, the erroneous £957bn figure was adopted and repeated in March by the Great British Think Tank, an organization whose tagline promotes "data, not vibes" and which asserts that every figure it uses is sourced directly from official public bodies. From there, the inflated statistic was absorbed into mainstream political discourse, ultimately manifesting in the Conservative Party’s "Right Way" publication in October 2026.
