This system suggests how long you need to wait until you're under the drink drive limit.
How to work out if you’re over the limit the morning after
Transport Minister hints at a lower drink drive limit
In December 2014, the Scottish drink drive limit was slashed from 80mg of alcohol per 100 ml of blood to 30mg of alcohol per 100ml of blood. This article considers the impact of Scotland's lower limit and what effect a lower limit could have in England.