Tim Collard, writing in the Telegraph, suggests that the units of alcohol is mere puritan propaganda.

Publishing units on labels is not going to change anyone's drinking habits; if anything, it will be like a badge of honour to the the serious abuser one would have thought.

In pubs etc. the measure has been strictly controlled by law for a century. If the consumer cannot judge for himself that he has drunk too much alcohol for his own good - then the publican by law must refuse to serve him. 

For off license sales, the strength of alcohol is indicated on the bottle by Alcohol By Volume - a much simpler system than the old proof: at 40% ABV what is difficult to understand? 40 % alcohol - 60% water.  What one pours for oneself is another matter. At home is rarely a recognisable unit measure. What next? The government making it law to use optic measures in the home?