YOU can always rely on Spanish car maker SEAT to put a smile on your face, even with the smallest, soberest city car.

The SEAT Mii (pronounced me) lines up alongside its sister vehicles, the Volkswagen up! and Skoda Citigo, but while they are being marketed as super-sensible four-seaters, the SEAT version has put its glad rags on.

Within weeks of the SEAT Mii going on sale in the UK, the striking Vibora Negra – which means black viper in Spanish – was unveiled.

Adding about £1,700 to the price of the Mii, the styling pack transforms a smart little car into a visually aggressive hatchback. Individual items are available to buy from dealers, so owners can pick and mix which elements of the pack that they want to buy. From twin stripes, 15-inch black alloy wheels and tailgate spoiler, to side skirts and mirror caps, it certainly catches the eye.

Just as eye-catching though is the cost of owning the car, which is powered by a low-emission, 1.0-litre, three-cylinder petrol engine, with a choice of 60 or 75 horsepower outputs.

With space for four adults and a decent boot, the car is nippy, lightweight and easy to manoeuvre around town, while still having sufficient beef to easily cope with long-distance motorway travel.

Build quality is superb and that translates into a comfortable, rattle-free ride. While it is the least expensive model in the SEAT range, the car has plenty of technology on board. Most prominent is the so-called SEAT Portable System, a smartphone-sized, removable device with a five-inch touchscreen that clips on to a dashboard-mounted holder.

It combines satellite-navigation, Bluetooth phone connectivity, an on-board computer and audio playback via SD card. Again, despite its size, the Mii has big-car safety features, ranging from anti-lock brakes and four airbags as standard across the range.

But most impressive is the availability, for £200, of the City Safety Assist system, which automatically applies the brakes in the event of a potential frontal collision. The system works at 19mph or below by using a laser mounted behind the rear view mirror. If an imminent collision is detected, the system primes the brakes and if the driver makes no effort to slow the car, it applies them — hard. I have tried the system in the sister VW up! and it works.

It should be fitted as standard. Lining up against an impressive array of rivals, including the Renault Twingo, Ford Ka, Fiat 500, Toyota Aygo, Citroën C1, Peugeot 107, Vauxhall Agila and Suzuki Alto, the SEAT Mii range begins at £7,845, meaning a Vibora Negra can be put on the road for under £9,500.

And with a three-year warranty, two-year European-wide roadside assistance package, and servicing at 20,000-mile intervals, there are a few more reasons to make you grin.

Auto facts SEAT Mii Vibora Negra

  • Price: £11,820
  • Insurance group: 2 (1-50)
  • Fuel consumption (Combined): 60.1mpg
  • Top speed: 106mph
  • Length: 355.7cm/140in
  • Width: 164.1cm/64.6in
  • Luggage capacity: 8.8 cu ft
  • Fuel tank capacity: 7.7 gallons/35 litres
  • CO2 emissions: 108g/km
  • Warranty: 3 years/60,000 miles