Several of the world’s biggest carmakers lobbied the UK government to try to weaken or delay rules to accelerate electric car sales and cut Britain’s carbon emissions.

Toyota, Jaguar Land Rover (JLR) and Nissan were among the companies to ask for delays in enforcement of the zero-emission vehicle (ZEV) mandate that obliges them to sell increasing proportions of electric cars or face heavy fines, according to documents seen by the Guardian.

However, Volkswagen, Ford and Tesla argued that the ZEV mandate should be tougher.

The lobbying was contained in responses to a government consultation shared with the Guardian by Tom Riley, the author of the Fast Charge, an industry newsletter.

In September, Rishi Sunak pushed back a ban from 2030 on all sales of petrol and diesel cars to 2035. However, despite delaying the flagship green policy, the government stuck with the related ZEV mandate plans to force carmakers to sell more and more electric cars each year. Under the ZEV mandate, 22% of new cars sold in 2024 must be zero-emission, a figure that rises steadily to 80% by 2030.

Carmakers’ responses to the new rules were heavily redacted, with pages of text blacked out at the carmakers’ request. Nevertheless, they reveal the arguments the companies made against one of the UK’s key policies to reduce its carbon emissions and reflect the uneven progress in the race between manufacturers to shift to electric cars – and the panic in some parts of the car industry that they could lose out because they are not shifting quickly enough.

The carmakers who backed delaying the full ZEV mandate argued that the rules came too late for them to change production plans to increase electric vehicle sales.

Japan’s Toyota, the world’s top car seller in 2022 but a laggard in the electric car race, said it was “extremely concerned” by the UK targets up to 2027, which would be “challenging for manufacturers like Toyota” and could cause financial and brand damage. Toyota has bet heavily on hybrid cars that combine a petrol engine with a battery, and has argued for a delay to fossil fuel bans to protect its Derbyshire hybrid car factory.

JLR has the most UK car factories, producing Jaguar and Land Rover cars, but is only now launching its second electric car, a Range Rover, five years after its first, the I-Pace. The manufacturer said it was “far from certain” that carmakers could hit the targets, and that “targets in the early years are set at unachievable levels”. The Vauxhall maker Stellantis and Japan’s Nissan also backed delays in different forms.

After the lobbying the government included “flexibility” in the final rules, including provisions to allow carmakers to miss targets in one year if they sold more in other years.

There was also a provision for manufacturers of fewer than 2,500 cars a year that exempts them from the rules until 2030. The British sports car makers Aston Martin Lagonda and McLaren both argued that they would be unable to meet the targets. Aston Martin said legal action against supposedly unfair regulations could follow.

Other manufacturers strongly backed the rules. The US carmakers Ford and Tesla argued that the government should force carmakers to sell even more electric cars.

Elon Musk’s Tesla, which pioneered electric car sales and has just been overtaken by China’s BYD as the biggest seller of EVs, said the rules were “not sufficient to drive more than organic market evolution” and said “it is possible that targets that look a stretch today will quickly be surpassed”. Ford said it “believes that the suggested trajectory can be met by many manufacturers across the UK market, and will ensure that those that are lagging accelerate their development appropriately, with the option of trading certificates to make up any shortfalls”.

Germany’s Volkswagen, the world’s second-largest carmaker, said the targets were “ambitious but seem to be generally feasible”.

Riley, who obtained the documents under freedom of information laws, said: “Clearly a lot of carmakers, whilst being enthusiastic about the EV transition in public, had reservations about these trajectories in private. It will be interesting to see how this manifests with the ZEV mandate kicking in from January.”

The carmakers were approached for comment. Toyota shared a previous statement welcoming the ZEV mandate and its inclusion of flexibilities, while a Stellantis spokesperson said the company had argued for enforcement of the mandate to kick in in 2025.

An Aston Martin spokesperson said the company had a “clear plan to have an electrified line-up of sports cars and SUVs” but shared specific challenges for smaller manufacturers. He added: “Aston Martin will be fully compliant with the regulations published by the government and will seek to achieve the targets set out.”