More than half of cars used by Government ministers are diesels, an investigation has revealed.
The discovery led to accusations of hypocrisy by industry figures who believe the Government is pursuing an anti-diesel agenda.
Forty-nine of the fleet of 84 ministerial vehicles are diesel-powered, according to a Government response to a Freedom of Information request submitted by motoring magazine Car Dealer.
This includes 17 Jaguar XJ, eight Land Rover Discovery, six Ford Galaxy and two Jaguar F Pace models.
There are also 16 Toyota Avensis cars being renewed this month, although it is not known what they will be replaced by.
Six electric Nissan Leafs, 21 Ford Mondeo petrol hybrids and a hydrogen-powered Toyota Mirai also form part of the fleet.
Car Dealer founder James Baggott said: "When the Government has waged a war on diesel car buyers, quite incorrectly so, it's staggering to learn that 58% of the fleet used by ministers - including the Chancellor, who has been leading the battle - are still diesel-powered.
"Perhaps the Government's fleet buyers know what we all do, that diesel is often the right choice for a lot of buyers.
"These mixed messages are damaging the car industry. Educating car buyers about choosing the right fuel for them must be at the forefront of ministers' minds instead."
Demand for new diesel models in the UK fell by 17% last year, Society of Motor Manufacturers and Traders (SMMT) figures show.
SMMT chief executive Mike Hawes said last month that many motorists are hesitating about buying diesel cars because of "confusing anti-diesel messages".
All new diesels are expected to be subjected to a one-band increase in the first-year vehicle excise duty rate from April 1.
Plans have also been unveiled to ban the sale of all conventional diesel and petrol cars by 2040.
Former Top Gear presenter Quentin Willson said: "When 49 out of the 84 cars used to chauffeur ministers are still diesel-powered, the Government isn't exactly practising what it preaches.
"You can't pontificate on diesel car pollution and then be driven home in one. Why, out of those 84 cars, are only six electric?"
Prime Minister Theresa May told the Commons in January last year that the Government Car Service is "working to remove diesel vehicles from its fleet".
A Government spokesman said: "These vehicles are being replaced as they become due for renewal with fit-for-purpose non-diesel alternatives that take into consideration operational requirements."