The UK legal system applies a separation of roles – there are two kinds of lawyers: barristers and solicitors. Only a barrister may address the court.
In old times, barristers would run their offices in local bars. Hence, Bar-rister, hence, the Bar Exam.
I personally prefer my lawyer sober, but that’s just me.
Bonus Fact 1: Like barristers, ‘Mind your Ps & Qs comes’ comes from bar houses. Bartenders in England used to tell regular costumers that drank too much and lost their manners to mind their Ps & Qs – that is to say, pints and quarts. It was later shortened and used in other circumstances.
Bonus Fact 2: The term ‘Bathtub Gin’ origin lies deep within the happy 20’s prohibition times. Back then, gin was a favorite in the underground acholic establishments, as it was quick and easy to bootleg. The term bathtub gin was coined in reference the way bootleggers mixed the spirit – since the bottles were too tall for regular sinks, and had to be filled under a bathtub faucet.