Does it really matter if Ken has a Scotch first thing?

For all the public health blether that gets spouted, it remains surprising how level-headed most people are when it comes to their boozing. Most understand fine well when they're drinking too much without having to count units. Speaking as a recovering alcoholic myself, I often think I have little useful to add to the debate. But from my own eight years' cleareyed observation of the tipplers that surround me, I can distil a few drops of wisdom.

First, there is the widely acknowledged truth that it's not the quantity that is drunk that defines whether you have a problem. Mostly the reaction of the individual to what he or she drinks is the key test: alcoholics abreact to booze. On one occasion they'll sip sherry in a civilised fashion, on the next - seemingly without rhyme or reason - they'll end up under Hungerford Bridge swigging fortified wine.

This unpredictability is also what distinguishes the true alcoholic from those who are alcohol-dependent but haven't yet bought the whole pathological packet. There are huge vats of such people in this country - how could it not be otherwise? Ninety per cent of British adults drink, many every day of their lives. We are an alcohol-dependent culture, relying on it as the lubricant for births, marriages, deaths and everything in between. But for the most part these citizens are not significantly more likely to develop a full-blown problem than others who barely sup.

Which brings us to the Mayor, who was accused last night, in Channel 4's Dispatches programme, of drinking Scotch at his Mayoral Questions at 10am one morning. A tad louche Mr Livingstone's behaviour may have been, but there's no way, in and of itself, that it means he's an alcoholic. Alcohol-dependent, perhaps, but that's quite a different thing.

Indeed, I'd suggest that the overpowering urge that some feel to judge others' drinking habits is itself a far more alcoholic trait than mere tippling. It's alcoholics who constantly seek to compare themselves in this way, usually selecting some skid-row type against whose excesses their own transgressions appear minimised. It's alcoholics who are obsessed by the minutiae of units and not drinking before X o'clock - because it's they who are unable to control themselves once they get started. Indeed, overall, the accusations against the Mayor - and the wider culture that they reflect - seem to suggest that some commentators shouldn't merely abstain from alcohol during January but all intemperance.