YOU might have noticed how diesel is fast becoming a dirty word, accused of poisoning pedestrians with pollutants as they walk through city streets on their way to work or the shops.

The rights and wrongs of that case are too complex to be debated here but what the diesel dilemma certainly does it make car buyers wonder if their next set of wheels really ought not to be powered by petrol.

Even without entering the fray there is reason to look at the choice of what you pour in your tank, purely from a financial point of view.

Simply put, today's better petrol engines produce the sort of economy figures that nudge into diesel territory. Then consider you'll pay more for the smelly stuff (and the car you put it into) and, if you don't cover stellar mileages, the case for turning to unleaded begins to stack up.

Take the angularly handsome Nissan you see here. Sunderland-built and latest in a model line that turned the company from also ran to spectacular success story after its launch in 2007, it sells in multi-thousands with either petrol or diesel doing the work.

The test car comes with the more powerful of two petrol engines on offer and provides enough performance for this handsome SUV to live up to its looks, so long as you keep the revs above the comfort zone you typically enjoy with a lazier diesel.

And over many hundreds of miles of mostly main road work the car showed 47mpg on its dashboard trip readout. Adjust that for the cheaper cost of petrol and it translates to about 49mpg, given parity with diesel on price.

That's a fine result. Then consider that going diesel will cost you £1,500 on this particular car and you would need to travel long distances to reap the benefits of a diesel engine's better economy.

A diesel would be a bit nosier in the cabin but a more relaxed drive, not needing the surprising number of down changes demanded in the petrol Qashqai as a long upward drag appeared. But hands that don't pong as you trigger the smelly diesel fuel nozzle at the pumps is some consolation.

Away from the tank, this latest Qashqai looks like an entirely logical development of the first car; a little lower, wider and longer than before, and a touch lighter too, to the benefit of interior room, luggage space and economy.

It is available in a wide range of trims (always the mark of a car that the market loves), priced from £18,265 for a car with a 1.2 litre petrol engine and front-wheel drive to a four-wheel-drive diesel at £28,500.

All share a body revised early in 2014 in a major revamp that left the Qashqai roots untouched (don't change a winner out of all recognition) but added a sharper look. Judging by the number you see, it's been a successful makeover.

Sitting near the top of the Qashqai tree, the Tekna is packed with techie bits, from cameras positioned around the car to give 360 degree views as you park, to another camera that reads speed limit signs and flags them up on the dash.