British MPs who lobbied the government to scrap its ban on petrol cars and instead back unproven fuel additives were led by a salesman for the products, a joint investigation by openDemocracy has found.

Last August, the ‘Fair Fuel’ all-party parliamentary group (APPG) published a 64-page report that urged the government to investigate the use of fuel catalysts, rather than going ahead with a proposed ban on petrol and diesel cars by 2030.

The report, which claims fuel catalysts are “proven to cut emissions and fuel consumption in fossil fuels”, states that it was “produced and paid for” by FairFuel UK, a campaign organisation that has opposed fuel duties and environmental measures for more than a decade.

But the report did not disclose that FairFuel UK’s founder, Howard Cox, also owns a business that markets a fuel additive called Ultimum5, for which he owns the trademark.

The investigation into Fair Fuel APPG, led by openDemocracy, Source Material and DeSmog, comes after openDemocracy lifted the lid on the murky “back door” lobbying world that has seen APPGs take £13m from the private sector since 2018 in exchange for access to Parliament.

Ultimum5 is owned by Cox, who is listed as the public contact point for the APPG, and his business partner, Lembit Opik, a former Liberal Democrat MP and reality TV star. Like Cox, Opik has denied the prevailing scientific view that man-made climate change is rapidly heating the planet.

Alastair Lewis, a professor of atmospheric chemistry at the University of York and an expert on air quality, told The Guardian that such fuel additives “come at [an environmental] cost, from the extraction of the raw materials through to the synthesis of chemicals, their packaging, sales costs and so on”.

He added: “What is often lacking [...] is quantitative data that shows just how much of an improvement they bring. Small marginal gains in environmental performance in the engine could be wiped out by the full lifecycle cost of making the additive. The marketing of additives often includes lengthy descriptions of plausible-sounding chemistry, but virtually never includes independent test data that shows improvements in performance in the real world.”

Overlap with Net Zero Scrutiny Group

One listed contributor to the Fair Fuel APPG’s report is the Global Warming Policy Foundation (GWPF), a think tank described by one critic as the “UK’s main club for climate deniers”.

GWPF recently rebranded its campaigning arm as ‘Net Zero Watch’, to highlight what it claims are the unaffordable costs of Britain reaching carbon neutrality. Conservative backbencher Steve Baker, a GWPF trustee who is best known as an organiser of the hardline pro-Brexit European Research Group of MPs, recently formed a Net Zero Scrutiny Group in Parliament.

Baker’s Net Zero Scrutiny Group overlaps with the FairFuel APPG. Conservative South Thanet MP Craig Mackinlay chairs both and has recruited GWPF staff to his office.

After receiving questions from openDemocracy, SourceMaterial and DeSmog, Cox told SourceMaterial he was resigning his directorship of Ultimum5. He denied there was any conflict of interest, adding that he had not made any money from the business and that Mackinlay was aware of his role.

“I’m very passionate about lowering emissions,” he said. “I’m resigning from Ultimum5. You have done your bit by rubbishing me.”

The APPG’s members include Robert Halfon, a Conservative MP described on FairFuelUK’s website as a “long-time supporter” and a member of the Net Zero group who urged the government to adopt fuel additives as a way of reducing harmful emissions.

Speaking in Parliament in July 2019, Halfon asked the transport secretary, Chris Grayling, to meet him and Cox to discuss the issue. Cox had already been approached by investors interested in acquiring Ultimum5’s patents out of administration.

Two months later, shortly after Cox secured the trademark for the Ultimum5 name, Halfon was quoted in support of fuel additives in a report about FairFuel polling on petrol and diesel costs.

“Not only do they work to reduce fuel consumption and help us to reach our climate change targets – they are a viable, cost-saving option for motorists and the Treasury,” he claimed.

The quote was later used for promotional purposes on the Ultimum5 website.

A spokesperson for Halfon said: “Robert has no shares in this, or any other company in a related business. He has consistently campaigned on behalf of constituents and motorists throughout the UK against further rises in fuel or tax duty.”