It can be difficult to make a decision which model to go for when buying a car, but it can be even trickier to decide between a petrol and diesel-powered vehicle.
Buyers also need to make sure they base their decision on not just fuel economy, as they are a number of other reasons, such as depreciation, that can have an impact.
In general, diesel cars do cost more than petrol ones to purchase, especially if you are in the market for a compact or a supermini. Larger cars tend not to have such a premium, but it is something to bear in mind – especially if you plan to sell your car in the future.
The key question for buyers is whether it costs more at the pump to fill up. The falling cost of petrol means the headline rate for fuel is much more attractive than it once was, but diesel is also benefitting from the lower costs. Generally, a diesel car will cost around five per cent more to fill a tank, but it will do around 25 per cent more mileage.
However, the real savings only tend to come if you drive more than 12,000 miles, as it will take a number of years to recoup the difference in purchase price.
Which? executive director Richard Lloyd explained: "Fuel price rises have been hitting household budgets hard, so it's important for consumers to know they're getting value for money when they buy a car.
"Diesel cars are known for their fuel efficiency, but with lower pump prices for petrol and a premium price tag for diesel cars it may make more financial sense for families to go for the petrol version."
Many diesel cars have over the years developed a reputation as being less refined that petrol counterparts, with reports that they can be noisy. However, this is no longer the case, they can be a little rough at low revs, but that so can turbocharged petrol cars. Diesels have the benefit of being able to allow drivers to change gears early.
In terms of insurance, there can be a difference in premiums, but it is very dependent on different models, so you will need to do your research. Generally, diesel can attract higher covers costs, but this is because they tend to be an option on larger cars and the difference may not be as high as you think.
There are some eco-friendly advantages offered by diesel cars as they use less fuel for a given mileage and therefore may cause less damage to the environment, especially if fitted with a special filter to process particles created by the fuel.
However, if looking for a green car options, then it may be worth looking at the growing range of hybrid and electric cars that are on offer.