DOWNSIZING and upsizing have their merits, but sometimes you wonder whether such an exercise may be to the detriment of related models within the brand.

Volkswagen's upsizing of the Polo is a prime example. In size (and looks from some angles) it closely resembles its big brother, the Golf, so much so that you have to look twice.

Admittedly close up the definitions become clear but from a distance it's not as easy to differentiate between the two. Accepting this, it is feasible that one model might impact on the sales of the other.

The German company has positively encouraged perception of the new Polo as a "small Golf", but so far, Volkswagen hasn't indicated that the less expensive Polo has significantly encroached on sales of the larger hatchback model.

Philosophically, even if the Polo wins converts from its more expensive big brother, the sales returns still go into the same financial pot. So it's still a win-win situation.

The latest updates on the Polo add to the perception of the mini Golf, but the visual tweaks are minimal with slight alterations to bumpers and lights.

The result is an even neater, trimmer supermini-city car which is at home in town or out and about on the highway. It is, without doubt, one of the bigger small cars in the supermini/city car sector.

The important changes are in the re-worked engines which boast better performance and efficiency with one of the most impressive being the 1.4-litre turbodiesel. It develops 89bhp, achieves 0-62mph in under 11 seconds and registers an official average fuel return of 83.1mpg, while CO2 emissions are a low 88g/km.

That is impressive - though under duress and taking in its stride umpteen short, stop-start journeys, the "mini Golf" managed a real-life mpg in the mid-sixties.

The three-cylinder unit proved to be a strong and willing powerhouse that does feel livelier than its sprint figure suggests, while engine noise is much more subdued than in a number of competitors, also powered by three-pot units. The five-speed manual gearbox is flexible and refined - like most of the Polo's mechanics.

The VW is ideally suited to trundling around town but equally it settles happily for top motorway cruising.

It is a very easy, light car to drive, and the steering is light and breezy - though, as with many city/eco cars, feedback is downright vague. The Polo handles reasonably well, too, while the ride is exceptionally civilised for a car in this category with the soft-ish suspension absorbing most ravaged road surfaces.

There's good, all-round vision apart from the restrictive smaller rear window and bulky rear pillars but front and rear parking sensors, standard on some models and on the SEL model here, help address parking issues.

Volkswagen continue the Tardis treatment with the Polo scooping out as much interior space as possible defying those compact external dimensions.

Three in a row in the rear is a cosy arrangement - especially with the restricted, narrow, middle squab, but it is acceptable for a child or a slim adult for a limited time.

Importantly for families, the designers haven't skimped on the door bins and other storage slots. They are generous and actually more useable than those found in most rival models.

The Polo has inherited many Golf components and features so it's no wonder it gets the "mini Golf" label. It is classy and well built and oozes quality and has many safety features as standard even from the entry model to include ESC electronic stability control, hill-hold as well as automatic post-collision braking system which brakes the vehicle after a collision to reduce kinetic energy, reducing the chance or gravity of a second impact.

This latter feature is added following research which showed that 25% of all traffic accidents involving personal injury are multiple collision incidents - where there is a second impact after the initial collision.

A price tag of £17,940 for the SEL spec (including £540 optional extra here on the test car for metallic paint) is fairly steep for a small hatchback but the Polo redeems itself with a long list of kit. This includes special 16-inch alloys, front fog lights with cornering function, front and rear parking sensors, cruise control, upgraded media system with 6.5-inch colour touchscreen, MDI multi-device interface with Lightning and 30-pin connectors, air con, variable load floor in boot, multi-function computer and electrically heated and adjustable door mirrors.