Research shows that our attitudes to alcohol have changed and our drinking habits are having an impact on our driving habits.

We've all seen the horrific advertising campaigns often on our TVs at Christmas highlighting the dangers of getting behind the wheel when you are over the limit. But there is a fine line between having one, and having one too many. If you go into a pub and order a pint of beer, that's exactly what you get and the strength would be clearly labelled on the pump. But if you ask for a glass of wine, as many ladies (and men) do, it's not always clear what you actually get – is it 125ml, 175ml or 250ml? And what strength is it? 10%? 12%? Or even 14%? What exactly are you drinking and could it tip you over the drink-drive limit?

The guideline for the legal drink-drive limit in England and Wales is three units for women and three to four units for men. A pint of 5% beer is 2.8 units and a 175ml glass of 12% wine is at least 2.1 units. However it is not an exact science. Alcohol affects everyone differently, with even small amounts affecting some people's ability to drive safely – factors include your weight, metabolism and even your current stress levels. So even though there are guidelines it's actually extremely difficult to give a blanket answer to how much anyone can drink to be 100% safe to drive. The advice is simple – avoid alcohol altogether if you are going to drive – zero is the best policy.

If you have had a drink, especially if you are at home where measures don't really exist, and get behind the wheel, you are risking your licence, your life and the lives of other road users. It's just not worth it. But we must remember that drink driving is a symptom of heavier alcohol consumption. We need to think about how we change behaviour and this is not just about drink driving but also about health and support services.

This issue really strikes a chord with me, not only because I have seen the reality of drink driving through years as a uniformed police officer, but I've also had a close female relative who battled with alcoholism. This has made me very conscious of my own drinking habits and I often ask myself if I drink too much – although I obviously never drink and drive. I know whenever I've had a health check, like so many people I've been very conservative in telling the doctor my weekly unit consumption.

In the UK our alcohol consumption is on the up, to such an extent that there is an ongoing debate around minimum unit pricing and tougher regulation. But something we really should be looking at is lowering the drink-drive limit. Not only would a lower limit help reduce consumption but it would make our roads safer and save lives. In England and Wales, the alcohol limit for drivers is 80 milligrammes of alcohol per 100 millilitres of blood. In most other European countries, as well as Scotland (which saw a marked reduction in failed breathalyser tests as soon as the law was changed in December last year), the limit is less, usually 50 milligrammes per 100 millilitres of blood. I think it's time we caught up.

Victoria Martin

Chief Inspector, Durham Constabulary