Charcoal! - Not Tremendously Good

You can't beat a real charcoal barbecue on a lovely Summer's evening but has anyone else noticed that charcoal doesn't burn like it used to.  I remember "in the good old days" returning to spent barbecues to find nothing but ash. Nowadays I am finding up to one third of all the "charcoal" that I use has not burnt.

I have tried many different brands in my search for charcoal that actually burns and so far I am not doing well, any recommendations??