Tories overstate net zero cost by nearly £500bn in apparent spreadsheet error

Kemi Badenoch’s flagship party conference policy document overestimated the cost of net zero by nearly £500bn, seemingly after someone accidentally double-counted figures on a spreadsheet.

The apparent error appears in a chapter on net zero in The Right Way, a 100-page policy document produced for the Conservative conference in Birmingham. Badenoch repeatedly used the phrase in her main speech.

Justifying the Conservatives’ decision to scrap the target of the UK reaching net zero emissions by 2050, introduced under Theresa May, the document says that estimates of how much this would cost the economy “have varied enormously”.

It goes on: “In 2020, the Climate Change Committee (CCC) estimated that its route to net zero would cost £957bn.” It cites the Sixth Carbon Budget produced by the CCC, the government’s climate change advisers, saying the report put gross economic costs at £1.4tn, falling to £957bn when savings were taken into account.

However, the figures in the report in fact total £478bn, half of what the Tory document said. The error appears to have arisen because a tally of all the costs in a CCC spreadsheet from the document also included the row showing totals for each individual column, thus doubling it.

A CCC spokesperson said: “We don’t recognise this number. The committee has previously offered to meet with Ms Badenoch and talk her through our advice. That offer is, of course, still open.”

The committee’s most recent analysis puts the expected cost of achieving net zero by 2050 at about £110bn, or about £4bn a year – 0.2% of GDP.

The error was spotted by the publication Carbon Brief, which informed the Guardian.

It is possible the Conservatives copied the figure without checking it. It appears to have been published in a report by the rightwing thinktank the Institute of Economic Affairs and also included in an article in the Spectator.

The Conservative document says it is intended to be a precise diagnosis of the UK’s problems. It is modelled in part on The Right Approach, produced by Margaret Thatcher’s Tory party in 1976, which set out some of the economic ideas later used in the 1979 election.

In a foreword, Badenoch notes that “as an engineer”, she is used to correctly diagnosing issues so they can be addressed. A later part of the report says: “To fix a problem we must first have an accurate understanding of what is causing it.”

The Conservatives and Badenoch’s office were contacted for comment.