MENTION a new car is 87mm wider, has a wheelbase increased by 95mm but overall is 2mm shorter than model it replaces yet there's bags of more room inside and most punters will be left confused and perhaps unable to comprehend what's going on.

The answer is to sit inside the all-new SEAT Ibiza supermini and the penny will drop.

However, UK motorists will have to wait until July to find out for themselves as that's when the fifth generation Ibiza arrives.

But impressed most people will be because the new five-door Ibiza - the three-door and ST estate versions have been dropped from the range - is the roomiest in the supermini class and along with its stylish looks and vastly improved interior furnishings and fittings it sets new levels for a car in this class.

Much of the extra space is due to the car's new platform - it's called the MQB A0 and SEAT is the first to use it in the Volkswagen Group - and with a body that is 30 per cent stronger, which the engineers call 'torsional stiffness', the latest Ibiza has a far more solid feel about it out on the road.

SEAT is lucky in being part of the Volkswagen empire since it can let its parents do all the engineering and technical homework on engines, chassis and the like and then cream off what it wants.

That allows the SEAT designers to come up with attractive looks and smarter interior layouts for their own brand of cars.

A simple solution of course and one that has paid big dividends for the Spanish car maker, originally regarded as a lame duck when VW took them over back in 1986.

Last year SEAT posted its best ever sales figures and Britain overtook both Spain and Germany as the biggest selling country for the brand.

The sales surge is continuing and in April SEAT became the fastest growing marque in the UK with year on year sales up 12 per cent.

With 3,926 registrations in the bag during the month it outpaced the likes of Honda and even MINI.

In 2016 SEAT sold more than 20,000 Ibizas in the UK and that figure will certainly be overtaken this year with this very impressive new model - even though it will compete against the top selling Ford Fiesta which itself is being renewed later in the summer.

The new Ibiza stands out from the crowd with striking and stronger bodylines. It also sits better with lower looks and has rather natty styled triangular front lights, all making the car more grown up.

It's certainly a totally different kind of supermini compared to the first edition Ibiza I drove down in Marbella back in 1984. That one was designed by the famous Italian stylist Giorgio Giugiaro and was regarded then as being very avant garde.

Times (and tastes) have moved on and the latest Ibiza is really impressive not only because of the vastly improved interior space and trim levels but the way the car actually drives - a crucial factor of course.

Relying on VW powertrains the new Ibiza has the 'in-house' three-cylinder 1.0-litre turbocharged petrol engine with a choice of 74, 94 or 114bhp outputs plus a new 1.5-litre petrol engine offering 148bhp which appears in the 'go-faster' FR model.

That version will naturally appeal to the younger brigade, particularly as SEAT says there are no plans for a sports Cupra edition in the new Ibiza range.

Most of the new line up has a five-speed manual gearbox, although the quicker versions do have a six-speed transmission, while the trim levels remain much as in the current SEAT model ranges, starting with the S, then SE, then the SE Technology with a choice of 74 or 94bhp followed by the more sporty FR trio and a pair of the top spec XCELLENCE models.

With the new engines and the new chassis the quality and refinement of the drive and ride are far better than on previous generations.

SEAT bosses expect the SE Technology model with the 1.0-litre 94bhp engine under the bonnet and coming in at £15,255 to be the lynch pin in the new range - and it's easy to see why because it has the ideal combination for most drivers in terms of performance and satisfaction.

It clocks in with an acceleration of 0 to 62mph of 10.9 seconds, combined fuel consumption of 60.1mpg, CO2 of 106k/km, sits in VED Band E, insurance group 11 and with a BiK rating of 20 per cent.

It's also exceptionally well equipped sitting on 15-inch alloy wheels and comes with LED daytime running lights, leather steering wheel, split fold rear seat (boot space is up to 355 litres on this new model), a five-inch colour touch infotainment screen, steering wheel mounted controls and plenty more.

For a driver looking for a cheaper option then the entry-level 1.0-litre 74bhp Ibiza S at £13,130 is a decent enough buy.

It too has Bluetooth connectivity, air conditioning, auto headlights, anti-lock brakes, hill hold control plus stability control and multi-collision braking system, all of which are included in SE versions.

Naturally the 94bhp engine has the edge on the 74bhp engine in terms of extra performance but both are extremely quiet and refined out on the road making them lively and responsive when needed and relaxing too.

Both the five-speed and six-speed manual gearboxes have a typically VW efficient feel with a nice, crisp movement up and down and are a real joy to drive even in heavy, stop/start traffic when lots of gear changes are needed.

Obviously, the sporty new 1.5-litre 148bhp engine will appeal more to the enthusiastic driver and again with the six-speed gear change it gives a stronger performance, including competence when driven hard round twisty, country up and down roads.

The Ibiza FR (also available with the 1.0-litre 94bhp and 114bhp engines and a DSG auto box) sits on better gripping 17-inch alloy wheels, has sports suspension plus, on the auto models, steering wheel mounted gearshift paddles. It also has a few more extras as standard inside with an eight-inch touch screen media system.

Top of the range is the XCELLENC with the 94bhp output 1.0-litre engine and comes in at £17,310.

The new Ibiza not only looks more classy but with that new chassis and those excellent performing VW 1.0-litre engines it drives and behaves much, much better than ever before. It's come a long way from Mr Giugiaro's original 30 odd years back.