"How big are you, are you a guy or a gal, have you eaten anything tonight, over what period did you sup your two pints..."

Plus what kind of beer is it etc. I've seen a graph for instance that shows a weak beer of about 3% would contain 4 units in 2 pints whilst a beer of 5% strength would contain 5.6 units in 2 pints. Not many are as low as 3% but of course there are beers of more than 5%. Going to get more ocmplicated for UK drivers as the Scottish govt is aiming to reduce the limit here!