A policy booklet recently published by the UK’s opposition Conservative Party features a prominent estimate on the "cost of net-zero" that appears to have been doubled entirely as a result of a fundamental spreadsheet error.
The policy document, titled "Right Way" and framed around "common sense" governance, argues that what citizens ultimately want from leadership is a government competent enough to solve the problems for which it takes responsibility. Within a section warning that sophisticated economic modelling should never serve as a substitute for traditional political judgment, the document takes aim at various economic estimates regarding the cost of transitioning the United Kingdom to a net-zero carbon economy.
However, the Conservative publication asserts—incorrectly—that the government’s official independent adviser on climate policy, the Climate Change Committee (CCC), had previously pegged the total cost of achieving net-zero at nearly £1tn. Specifically, the booklet states that in 2020, the CCC estimated its route to net-zero would cost £957bn.
In reality, the CCC’s actual figure published in 2020 was exactly half that amount, standing at £478bn. Furthermore, the committee released a revised figure of £108bn last year, a sharp reduction driven largely by the rapidly falling costs associated with electric vehicles (EVs).
The Conservative Party’s erroneous £957bn claim appears to stem from a calculation error originating in an entirely separate report, which accidentally accumulated figures twice while analyzing a public spreadsheet released by the CCC in December 2020.
The spreadsheet in question contains a detailed table outlining the incremental investments required to construct a net-zero economy across multiple sectors, ranging from low-carbon electricity generation infrastructure to domestic heat pumps and electric vehicles. These extra capital expenditures, designated under the category of CAPEX, accumulated to a total of £1.38tn over the 30-year timeframe spanning from 2020 to 2050. These projected capital investments were then weighed against anticipated operational savings, categorized as OPEX, which were calculated at £0.90tn over the same period.
When offset against one another across the 2020 to 2050 horizon, the combined net figure of these CAPEX and OPEX projections results in a total cost of £478bn.
Alongside the annual sectoral figures, the CCC’s 2020 spreadsheet also included a summary line providing combined annual totals for each individual year. Investigation into the origin of the higher figure indicates that an analyst inadvertently added all of these annual cumulative numbers together on top of the base figures, effectively counting both the operational savings and investment costs twice.
This double-counted calculation yields a cumulative net-zero cost of £957bn, which matches the exact figure cited in the Conservative Party’s recent policy booklet.
When the CCC originally published its landmark sixth carbon budget in 2020, it emphasized that the true net cost of £478bn amounted to less than 1% of the United Kingdom’s total gross domestic product (GDP) spread across the 30-year transition period. The committee pointed out at the time that the massive infrastructure investments 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 approximately 2%.
Subsequent updates from the advisory body have only reinforced these economic trends. In 2025, the CCC revised its investment cost and operating savings projections to £670bn and £562bn respectively, leaving a net total of £108bn across the 25-year window from 2025 to 2050—representing less than 0.2% of GDP. Earlier this year, the committee underscored that completing the emissions reduction pathway to net-zero would cost less than a single historical fossil-fuel price shock, while delivering direct consumer and societal benefits valued at roughly £110bn annually.
Despite these official figures and public clarifications, the erroneous £957bn statistic has experienced a traceable paper trail through various economic think tanks and commentary platforms prior to its adoption by the Conservative Party.
The erroneous claim in the Conservative publication formally cites the CCC’s 2020 guidance regarding the UK’s sixth carbon budget. However, that official advice contains no mention of the £957bn figure.
The earliest public appearance of the £957bn figure online traces back to an article published on January 12, 2026, in the Spectator magazine. Authored by David Turver, a retired engineer who describes himself as an "accidental energy analyst," the piece utilized the inflated sum in a critique of climate policies.
Just one day later, Turver repeated the mistaken figure within an extended policy report published by the free-market Institute of Economic Affairs. That report explicitly cited figure 5.3 of the CCC’s 2020 supporting advisory documents.
However, the underlying CCC spreadsheet that generated figure 5.3 strictly totals £478bn—precisely half of Turver’s cited figure. The discrepancy arose because the analyst summed every individual row in the spreadsheet without accounting for the pre-calculated annual summary line, producing a classic double-counting error.
The propagation of miscalculated figures did not stop there. Turver’s initial report subsequently spawned a wave of exaggerated headlines across various media channels, with some outlets falsely claiming that net-zero would cost between £7.6tn and £9tn. Those even higher figures relied on extreme underlying assumptions, including the theoretical premise that fossil fuels, alongside the combustion engine cars, domestic gas boilers, and power plants that consume them, possess zero economic value or cost.
Following the circulation of Turver’s report and his Spectator commentary in January 2026, the £957bn figure was repeated in March by the Great British Think Tank. That organization features the promotional tagline "data, not vibes" and asserts that every statistic it publishes is sourced directly from official public bodies.
By October 2026, the identical figure successfully migrated from these free-market think tank reports directly into the Conservative Party’s official "Right Way" policy booklet, embedding the spreadsheet error into mainstream political discourse surrounding the UK’s long-term environmental commitments.
