Amazingly it still works, as in supplies power to the laptop, but ejects a shower of sparks from the hole every time it is plugged in. It then glows red and after 10 minutes the plastic begins to melt and bubble, but the fuse does not blow and it continues to get hotter...
Apple needs to take note of this in the same way as the fake iPhone/iPad chargers - looks like they're all dangerous... Is this an unwanted side-effect of Apple doing something to devices to prevent the use of imitation accessories?!
Rather than buy another cheap imitation charger, I opted to once again repair my original Apple charger, pictured below, which now has exposed wiring and must be the crudest fix in the history of electronics - yet it has been working fine now for 6 months... eclipsing the entire working life of the fake charger by 5 months!
The next time this breaks, I'll be removing the split cable entirely and soldering in the intact one from the burnt-out charger - I would advise doing this from the word go if you buy a fake charger.