No Case for Change
It now seems that the government is likely to promote a reduction in the drink drive limit. The proposal would essentially cut the limit to 5/8 of the existing limit. There is no cogent case to support this change, and a number of significant reasons against it.
Whilst there may a pressure from Europe to "harmonise" drink-driving levels, there is no apparent necessity to do so. It is hardly likely to damage the single market or interstate trade to have different limits in different countries (and indeed in any event the limits are not universally the same). Nor is that put forward (at least at the moment) is a reason necessitating the change or even rendering it desirable.
Offences based on the level of alcohol in blood or breath are not "conduct" offences. You could be driving perfectly properly and still be guilty of an offence. The genesis of the offences was the difficulty in proving that a driver was "drunk". The idea being that the level of alcohol should be fixed at one at which impairment would be regarded as sufficient to constitute criminal conduct per se. That level has been operated in this country for a long time. There has been no carefully considered study demonstrating that the limit was wrong, nor groundswell of opinion from any section across the years that the limit had been wrongly set. That is no basis upon which to criminalise conduct.
Whilst it is true that drunken drivers are a cause of accidents, such people are caught by the present law. What the change would do would be to bring within its scope those who have a couple of glasses of wine with dinner. Such people could not conceivably be described as drunk. Most people who limit their drinking know to be extra cautious if any alcohol has been consumed at all. There is no suggestion that such people would be as or more likely to be a cause of accidents than a host of other forms of driving. Driving too close to the car in front is a particular cause of accidents. People who drive improperly can be guilty of careless or reckless driving. The whole point of the prescribed blood or alcohol limit is to fix an impairment level that is sufficiently serious that of itself it should amount to a criminal offence. There is simply no cogent basis, judged by that criterion, for changing it.
One of the more ludicrous suggestions is that the culture of binge drinking should lead to a change in the law. That is a bit like suggesting that an increase in gun crime justifies a change in the definition of common assault. Binge drinkers will either be stupid enough to drive anyway or will not drive so that they can undertake their binge drinking. If binge drinking is set at the level of a couple of glasses of wine with dinner then it is perhaps more prevalent than would otherwise be supposed.
Indeed change will have a number of undesirable side effects. It will inevitably mean that "drink-driving" will be associated with potentially modest levels of consumption. It will tend to reduce the perceived severity of the offence itself. It is likely to involve a lot of police time being applied to "soft" targets rather than clearing up crime. It is likely to enhance any perception that the police are there to extract as much money as possible in respect of trivial offences rather than get on with the business of pursuing serious crime. It will do no conceivable good whatsoever.