Also just remembered, I was out in the city one evening and had parked the car with the intention of getting a cab home with a mate. We were both stuffed from work so had a few beers over the space of 4 hours or so and got chatting to one of the bar staff who showed us a device that sits on the wall where you put $1 in and get a straw to blow into the machine and get your blood alcohol reading.

Apparently these machines are popular Oz wide. I felt OK but knowing full well how sometimes people feel OK but are over, I wasnt going to risk it until I tried this machine. I was well under the limit so able to drive home.

Then a few months later we went out with a larger group with the intention of seeing who could get the largest reading. I didnt get it unfortunately. Point is, do they have anything like that in the UK? Excellent idea IMO