WHEN a car as important to BMW as its 1 Series hatchback comes around for a refresh you can bet the designers laboured long into the night on the tiniest detail.

How about making the exhaust pipe a little bit fatter because it gives the back of the car a more sporty look?

Tick that one off among a host of changes to a model that claims one in five sales to British buyers of new BMWs and is expected to find 30,000 homes here each year.

You need to be a bit of a BMW anorak to spot the new tailpipe but changes to the lights at both ends give the latest 1 Series a wider, bolder look.

Inside, the cockpit is still aimed at serious drivers but there's a modest injection of extra pizzazz with added gloss black and splashes of chrome.

But it's under the surface where BMW has made its more important changes, starting with the choice of a new diesel engine (largely shared with a Mini Cooper D) that promises more than adequate performance and startling (theoretical) economy.

More powerful diesels are offered too, along with a range of petrol engines that climax with the M135i and its 155mph potential.

And for those critics who said BMWs were too meanly equipped for the money, comes news that every new car from the company - from cheapest 1 Series upward - will have satellite navigation as standard by September.

That doesn't mean you will be short of the chance to spend extra on options, of which there is long list, from metallic paint (£550) and a £600 sound system upgrade to active cruise control (£790) and a £330 reversing camera.

Even so, standard kit across the new range (which extends from £20,245 to £31,730 at the moment) is more generous than reputation has, ranging from DAB radio and Bluetooth to a big colour screen on the dash, climate control and LED lights at the rear.

Most buyers are happy to pay £1,000 more for a Sport package of different alloys, steering wheel and body styling tweaks or even find £2,700 for an M Sport package of bigger alloys, LED headlights, styling additions and firmer suspension.

Whichever version you end up with it will be a notably well finished car with plenty of room in the front, adequate space in rear for grown ups and a reasonably sized boot. If you need extra space at the expense of losing that sporty feel, BMW will happily point you towards the new 2 Series mini MPV.

Out on the road in the most economical version of this latest 1 Series you soon enjoy the characteristic thrum from its three-cylinder diesel engine (distant but mildly sporty) and relish the way it moves the car with enthusiasm.

A crispy, firm gearchange and well weighted steering combine with a ride that stays firmly in control without ever descending to discomfort to make this a car that covers ground with real enthusiasm.

And with fine economy too. A brisk drive over some challenging Wiltshire roads saw 57mpg on the trip computer, with a gentler session tipping the figure well into the 60s. That's a commendable figure and a realistic aim for a long term owner too.

The £395 worth of front sports seats were superbly comfortable, lacking only adjustable lumbar support (£230 extra) as a final flourish.