There are many handy things about having custody of a white BMW 5 Series for seven days. Did you know, for example, that no-one seems to want to hold you up in the fast lane of any motorway? This, as well as many other things, I have learned.

I’m not in the habit of using full beams to tan the necks of anyone in front of me, so it was initially strange to note how many people shifted into the middle lane as I traveled along the M4 last Monday night. Then the penny dropped. I too would get out of the way of any white BMW long before it had the need to switch on the tell-tale blue lights hidden in its grille.

Who buys it, how does it sell?

The 5 Series’ combination of speed, economy, safety and reliability might make it popular with The Law, but these factors are also some of the main reasons why it’s also a big seller with Britain’s executive classes. I examined the SMMT’s data and this shows that in the first half of 2012, sales totalled 10,695 units. That places the 5 Series second in its segment behind the Mercedes-Benz E-Class (13,297) and some way ahead of the Audi A6 (7,498).

The mechanicals

The car BMW lent me had a six-speed manual gearbox, which shouldn’t have been a surprise as so many UK buyers in this segment still seem to like changing gear themselves. It wouldn’t be my preference but there you have it – each to their own. The upside, and it’s a big one, is excellent economy.

By the end of the week I had averaged 50 mpg exactly after a high of 51.6. That was from a mix of stop-start city traffic, a run to Heathrow and back and a weekend trip on motorways and A-roads to Cornwall. I just checked the official Urban consumption average and would you believe it, it’s also 50.0 mpg. It’s good to know that real world numbers can equal those achieved under the European Commission’s test cycle.

You won’t mistake the 520d for an M5 when you put your foot down but for what’s been designed as the economy special version of the 5 Series range, a zero to 62mph time of 8.2 seconds is respectable. Top speed is claimed to be 144mph (231km/h). Power from the 2.0-litre four-cylinder turbodiesel engine is 184bhp (135kW) at 4,000rpm with maximum torque of 380Nm developed at 1,900rpm.

The inside story

The interiors of 5 Series BMWs and me were not the best of mates for over decade – the previous two generations I just didn’t like at all, especially from behind the wheel. There was something about the strange curves of the door pulls, the over complication of the SatNav switches and other controls that just didn’t do it for me. How, I wondered, could the company that once did the best looking interiors lose its way so badly? Still, the quality of the switchgear was never in doubt.

Happily, the latest car has a great interior. Ideally, I’d love to see the centre console angled even more towards the driver but there again, there’s nothing wrong with everything also being within reach of your passenger. That person might also take special delight from scrolling through all the menus of the centre console’s controller as it’s closer to them than it is to the driver. I found it simple to use and located everything I wanted quickly.

My test car had a shiny aluminium fillet that ran across the dash, with elements of that detail repeated on the door trims. These also had soft red down-lighters which somehow gave me a bit of a sense of well-being. Funny how we can learn to associate certain lighting with different emotions: so-called ‘theatre’ lighting is calming in a car for me.

The first time I slid behind the wheel of the 520d I thought of the instrument graphics of one of the first cars I ever fell in lust with. Surely it’s no coincidence that the original 3 Series had dials that didn’t look too dissimilar to those which greet the driver of the latest 5 Series.

No doubt the numbers and letters of BMW instrumentation are the same patented font as they have been for decades and the grain of the plastics might not even have changed too much either – if any company could have endearing OCDs about such things it would be BMW. The heavy-to-push and long-throw clutch pedal, the thick carpets and stalks that have not one milimetre of looseness in their action are all part of it. They conspire to make you feel you’re in a solidly engineered car that could only be from Munich’s most famous automaker. And as sales of BMWs prove, it clearly works, especially in the UK.

Cool stuff

Intelligent design abounds inside this car: the one cupholder in the centre console has an adjustable clip which will snugly hold what seemed like any size diameter bottle, so there can be no irritating rattle or worries about your drink tipping over. Other little touches include the switch you flick to switch the electric adjustment from left to right mirror – it has no labelling but it’s right where you’d expect it to be. BMW has rightly decided that if you use your brain, you’ll quickly work out what it does.

There was something else I liked which happened every time I locked or unlocked the car when it was dark. There are little lights in the exterior door handles and they must be LED as the light they emitted was pleasingly close in shade to the bright white of the paintwork. Striped red elements in the tail-lights also shine brightly when you hit the blipper.

The driving experience

The strength of engineering and intelligent design in this car runs deep so you can tell I’m struggling to find things to criticise. Certainly, this car easy to see out of and I was able to easily find a comfortable driving position – a three and a half hour run from home to see friends in St Austell saw not even a hint of back pain from self or partner. As for parking, that was dead simple, though the test car had front, side and rear sensors.

There IS something I want to mention about that driving experience that I didn’t enjoy and that was the manual gearbox. I got used to the clunky shift and long-push pedal but I’m not sure I could get on with the stop-start system. The problem is that the gear lever wobbles from side to side the moment the engine cuts out or back in and the engine surprised me by being quite rattly as it fired up: not very premium when cheaper cars like the Megane I have this week are superior on both counts.

Something else the Renault has over the 520d is better gearing and lower weight: I had to accept having to shift down to second for medium-speed roundabouts in the BMW as to stay in third would be mechanically cruel. I would have to have an automatic gearbox if I bought one of these cars as the constant fourth-third-second then back up to third-fourth-fifth routine into and out of roundabouts would be tiresome.

One more negative observation before I get back to the things I loved about the car. I will say this again: what is so wrong with handbrakes or even foot-operated parking brakes? The one on the car worked well but it took some getting used to. If you’re starting off on a steep hill, the car can roll back for an anxious second as you release the parking brake and that’s not a nice feeling. Dear global car industry, please tell your suppliers that I miss being able to have a proper handbrake with which to make smooth hill starts.

A minor moan was me wondering why there was no natural place to put the blipper. This gadget also surprised me by being attached to a very 1970s black leather keyfob complete with metal BMW shield – the kind of thing you might find in Halfords. I eventually settled on a slot in the door pull but then I had to extract it first before I could open the door. Maybe I should have left it in the ashtray (yes, the test car really did have one of those).

Enough of the stuff that makes the 520d less than perfect and back to where it shows why people buy it. The motorway is where this car feels most at home and at legal limit cruising speeds of 70mph it’s solid as a rock and a relaxing place to be. Above that? How about at, say, 100mph for miles and miles late at night on the M4? I couldn’t possibly comment but I’m grinning as I write that.

Should you buy one?

At just over £30,000, I can see why the 520d EfficientDynamics holds such appeal. For reasons mentioned above, an automatic gearbox would be the first option box I would tick and as the ride comfort is very good, I’d spec some big alloys purely for their looks.

One of the criteria I use to assess any car that comes to me for a road test review is whether I am ready to hand it back at the end of the week. This one, I would have rather kept. That’s got to do with the rear-wheel drive chassis which has been expertly set up for UK roads. Once you’ve joined a motorway and slipped the gearbox into sixth, it will just devour the miles quietly and oh so efficiently.

If you already drive an older four-cylinder 5 Series diesel, you’ll love this latest model and if you’re considering an E-Class or A6, I would definitely recommend a test drive before you sign up for either of those rivals. And if the CO2 number doesn’t matter to you, give the 535d a try. You’ll be looking at around £44,000 for one of these but you get 313bhp and a zero to 62mph time of just 5.5 seconds. With an Urban economy figure of 44mpg. And a standard (eight-speed) auto transmission.

By Glenn Brooks