According to the analysis, the weakening of the UK government's rules on electric vehicle sales may lead to a significant increase in carbon emissions as plug-in hybrid sales increase.

According to modeling by the Transport and Environmental Activities Group T&E, easy rules could generate up to 500,000 additional plug-in hybrid electric vehicles (PHEVs) on UK roads. PHEVS combines small batteries with contaminated gasoline engines and is more profitable than pure battery electric vehicles.

Experts say emissions will increase significantly due to the Labor government's policies. Transport Minister Heidi Alexander told Parliament last month that weaker rules, known as Zero Emission Vehicles (ZEV) Authorization, would “no neglect carbon emissions” of cars sold in the UK.

The government weakened the rules last month that forced automakers to sell more and more battery-electric vehicles each year to meet UK climate goals. Keir Starmer argues that the government needs to help struggling automakers, allowing more "flexibility", which means automakers can sell fewer electric cars and avoid fines.

"The government changes will allow automakers to sell more plug-in hybrids and longer. Instead of accelerating the transition to zero-launch cars, the industry can maximize sales of lucrative PHEVs, which are well beyond what is claimed to be much more than what is claimed."

According to the analysis, PHEV sales have almost doubled in some years. Now, PHEV sales are expected to peak in 2028, at 280,000 a year, up from the previous 2025 annual forecasts of 180,000.

"This will not only lead to sending more CO2 in the climate crisis, but it will also hit the UK's wallet drivers," said Colin Walker, head of transport for the campaign's energy and climate intelligence.

He said the UK government “distracts manufacturers to build the electric vehicles on which the future of the UK auto industry depends”.

Alexander's emissions statement appears to be based on government policy, which has been criticized by experts on reliance on unrealistic figures. Crucially, the government's analysis assumes that PHEVS will continue to gain the same market share as in 2024 - although generous emissions assumptions have made manufacturers huge incentives to sell more hybrids.

The PHEVS has a contaminated gasoline engine, but can run as much as possible on rechargeable batteries, saving a lot of emissions. In an ideal world, PHEV owners will use batteries for most small trips, with only the engine for longer trips. However, many studies have found that PHEV drivers do not reliably charge their vehicles, meaning that cars send more in the real world.

The EU is updating official figures to reflect the gap. By 2028, the average PHEV emissions will be 109 grams of CO2 at 109 grams per kilometer, higher than the current average of 32 grams used. But despite the December Ministry of Transport acknowledging that PHEVS "has higher CO2 emissions in the real world", the UK government will continue to use the 32g average. This will allow automakers to sell more PHEVs strongly as they will get credit for lower emissions, which means they have to sell fewer electric cars.

New Automotive CEO Ben Nelmes, who follows the Zev authorized IQ, said: "The government - and anyone who bought a car knows that manufacturers claim about MPG ratings should be taken with the help of a lot of salt. However, the ministers decided to put the UK's largest climate policy out of the accuracy of these proportions.

"This sounds naive to most people. We shouldn't be surprised that the UK's emissions are slower due to the recent changes in electric vehicle targets."

"The government can still mitigate some of the additional emissions caused by the vulnerability by formally acknowledging the reality of PHEVS emissions. This will lead to the real climate impact of the hybrid and make buyers aware of the extra costs they have in the pump," said Dexter of T&E.

A DFT spokesman said: “Our recent changes have reached a practical balance – giving manufacturers the flexibility to sell plug-in hybrids until 2035, while adhering to our commitment to new petrol and diesel vehicles in 2030.

“These changes are a practical and balanced approach that supports drivers with minimal impact on emissions, provides long-term certainty to the industry and protects jobs across the UK.”