The B Class is a funny car - the name seems to be the only thing that shows how it fits into the Mercedes range, the German manufacturer clearly having found a niche that no-one else knows about.
It's designed to offer something a little larger and more practical than the A Class, but isn't quite as good looking as that car and for a bigger machine it still only offers five seats where there are many cheaper rivals that would manage couple of crucial extra seats even at this level.
If you're looking for out-and-out space, though, we don't think you'll find any in the Mercedes range offering more room for driver and passengers until you reach the heady heights of the R Class and the massive GL. The humble B doesn't have quite the same executive image, though.
It does take on many of the A Class' qualities - the great use of space inside, the indifferent handling (an over-protective ESP has been in place on these tall models since the A Class tumbled over during a handling test in the late 90s) and firm urban ride are all carried over. The B can also get a little pricier than it really deserves to, which again is something it has in common with its baby brother.
Refinement on a motorway cruise is as respectable as you would imagine from a Mercedes - the cabin is hushed and quiet even as you leave the national speed limit behind. That said, you won't get far beyond 70 with the entry-level engines on offer. Your best bet is the B180 CDI, which is packed with torque but will set you back more than £21,000.
What you do get for trading up from an A Class is a plusher cabin, the materials feeling as suitably upmarket as you'd expect from a Mercedes. The B Class can much better justify the smug feeling you'll have inside from driving something much nicer than whatever family MPV is sitting next to you at the traffic lights.
You're going to have to want a Mercedes badge on the front of your car pretty badly, though, because the people driving that family MPV will have doubtless paid a lot less than you for what they're driving. The B Class has its work cut out to justify its high price and its entire raison d'etre, which it doesn't quite seem to manage.