YOU sometimes wonder why it takes so long for someone to come up with the simplest, most obvious ideas.

Take sliding doors on family cars. There have been sliders on people carriers for donkeys' years, it's just that they haven't been used to maximum effect - until now.

Ford's new B-MAX multi activity vehicle, based on the Fiesta but longer and taller, is a mould breaker and a car destined to prove a massive hit with families both young and old.

It's trump card is something Ford calls the Easy Access Door System, different to anything we've seen before in that it doesn't have a centre door pillar.

The front doors open in the traditional way but the rear ones slide back into a groove, leaving a vast side opening - around twice the width offered by competitors with alternative door concepts.

It's clever and practical. Those days of awkward manoeuvring for a mum trying to secure a child seat are well and truly over. In fact folding down the front passenger seat provides an ideal perch for facing the little ‘un and securing the belts.

By the same token, if an elderly passenger needs back bench access it's a simple case of stepping in or out.

And if you are concerned that this set-up may compromise safety, fear not, because the B-MAX is the third Ford model - after the Ranger and Focus - to be awarded the highest possible safety rating by crash test authority Euro NCAP.

It follows more than 5,000 computer simulated crash tests, 40 complete crash tests and a further 100 tests which involved the car being mounted on a sled and fired into a barrier.

Even though there's plenty of interior space with ample head and legroom for four adults and a child, the load combinations are exceptional for what is essentially a small car.

As an example we were able to fold down the seats and arrange a pair of 7ft flat packs, three large square boxes, a surf board, a lawnmower and some oddments - and still close all the doors properly.

But the B-MAX isn't just about accommodation because there's the latest technology too.

The newcomer actually marks the UK debut of Ford's voice-activated SYNC system which not only allows Bluetooth and music streaming but can also connect the car to emergency services and automatically send out location info.

Prices start at £12,995 for the 1.4-litre petrol engined Studio version, which precedes Zetec and Titanium in the three trim grades and the powerplants also include the new 1.5-litre TDCi and International Engine of the Year for 2012, the 1.0-litre EcoBoost petrol.

The latter comes in two power outputs, 100 and 120ps, with a £600 premium separating them.

I drove both on an 80-mile test route taking in country lanes and motorway and while the higher powered of the pair is an outstanding unit with loads of power on tap, the 100ps version is plenty strong enough for most requirements.

Most economical of the line-up is the 1.6 TDCi diesel boasting a claimed 70.6mpg compared to the EcoBoost 100's figure of 55.4 and the 120ps version's 57.7, achieved thanks to Start/Stop.

That said, this is not a diesel market, the lion's share of the B-MAX customers likely to be retail buyers who probably wouldn't cover the amount of miles needed to make diesel worthwhile.

Studio grade cars have manual five-speed transmission but just the 1.4-litre 90ps petrol engine and come with standard kit like body colour bumpers, adjustable load floor in the luggage compartment, fold flat front passenger seat, electric door mirrors, one-touch windows and a low tyre pressure deflation detection system.

Zetec starts at £15,600 and includes SYNC at no extra cost - usually £250 - while standard kit over Studio includes 15-inch alloys, halogen headlights with LED day running lights, front fog lights, leather trimmed steering wheel and gearshift knob, air-con, child observation mirror and heated windscreen.

Moving up to Titanium starts at £17,595 and adds SYNC, driver's and centre rear seat armrests, driver's seat adjustable lumbar support, cruise control, automatic headlights and rain-sensing wipers, heated front seats, Ford Power start button, Sony DAB digital radio/CD, 16-inch 15-spoke alloys and high gloss upper and lower grille surrounds.

Whichever model though, the B-MAX is a car of terrific versatility. It drives beautifully, is simply laid out, the materials feel of good quality and it looks good too. It's another example of Ford at its best.