The boss of Jaguar Land Rover has said it will not slow its move to electric cars even if the UK government delays the 2030 ban on new petrol and diesel models.

Adrian Mardell, JLR’s chief executive, said the company’s “plans will stay the same”, after the prime minister, Rishi Sunak, failed to publicly back the 2030 deadline amid pressure on the government’s net zero plans.

JLR, which on Tuesday reported a rise in sales of its Jaguar and Land Rover cars, last week committed to making electric vehicles using batteries from a UK factory in a £4bn investment.

Banning new petrol and diesel cars by 2030, followed by a 2035 ban on hybrids, was a flagship policy of Sunak’s predecessor, Boris Johnson. Some Conservative MPs and some in the car industry have called for the deadline to be pushed back, arguing that it would help British manufacturers and save car buyers money.

However, the housing secretary, Michael Gove, on Tuesday told Times Radio that the date was “immovable” and remained government policy.

Mardell said: “I suspect a version of this discussion will take place in the background. From our perspective, stability is important. Our plans will stay the same.”

He claimed that electric vehicles using current lithium ion battery technology would always be more expensive than petrol or diesel versions – in contrast with the forecasts of some analysts who expect costs to fall. Carmakers tend to plan their products over the course of several years, giving them limited room for manoeuvre when government policies change.

Tata, JLR’s Indian owner, revealed last week that it will build a gigafactory in the UK, ending months of concern within the British car industry that it might choose Spain for the new factory. The move will firmly shift Britain’s largest automotive employer towards electric vehicles, and has sparked hopes that a broader UK battery industry will grow.

Mardell said JLR engineers would be deeply involved in the battery technology and development. He declined to address reports that Tata would partner with the Chinese supplier Envision to develop the technology.

JLR has been slower than some rivals to embrace electric cars. Its only pure electric model so far is the Jaguar I-Pace, which is produced by a contractor in Austria, but its first all-electric Range Rover goes on sale in 2024 ahead of a barrage of new electric models.

JLR said it had seen continued strong demand for the existing versions of its Range Rover, along with the slightly smaller Range Rover Sport and the new Defender.

JLR made profits before tax of £435m between April and June, compared with a loss of more than £500m a year earlier. It produced its most cars in more than two years, leaving behind supply chain problems that had plagued it since the disruption of the coronavirus pandemic.

Mardell was confirmed as permanent chief executive this month after taking over from Thierry Bolloré, who quit unexpectedly in November.