AND THE FASTEST Yaris in the line-up is… the 1.4 litre diesel. It has no trouble dismissing the 1.0 three- cylinder, and makes light work of the 1.3 petrol too, needing 10.7sec to reach 62mph in contrast to the petrol’s 13.1sec. And as you’d expect, it’s the most economical Yaris, too, turning in 62.8mpg to the 1.3’s 48.7mpg. But unless economy is everything, this is not the Yaris to buy.The reasons why are evident as soon as you fire up. Unlike most modern oil-burners, which calm down after they’ve warmed through, this motor plays endless variations on the rattle, clatter and thrum themes, only quietening when you back off the throttle. So it’s noisy. And the engine’s extra weight burdens the Yaris considerably. Not only does the steering weight up in unappealingly glutinous fashion, but the car feels decidedly less nimble than the 1.3.The ride deteriorates, too, turning pattery too easily. So even if you aren’t a keen driver, there’s a dynamic price to pay for choosing the oil-burner.Of course, the diesel Yaris isn’t all bad. Even though you must work the gearbox to get the best of the engine – the torque curve starts sinking away beyond 3000rpm, a long way before the 5000rpm cut-off – brisk progress is quite easy to achieve, and you do get used to the car’s friendly clatterings.And then there’s the rest of the Yaris, which is generally excellent – well packaged, easy to use, decent to look at and well assembled, if from low-grade plastics in places.But the killer blow is the Yaris diesel’s price, which is £1000 more than the 1.3 petrol. That’s too much when the premium for a diesel Renault Clio is £900, a 206 £750 and a Ford Fiesta £600.