The long-running series in which readers answer other readers’ questions on subjects ranging from trivial flights of fancy to profound scientific and philosophical concepts
-
This week’s question: When does a reasonable train route become unreasonable?
Why is sugar-free tonic water always described as “slimline” (at least in the UK)? As far as I know, every other sugar-free drink takes the label “diet”. I presume the reason is historical – and possibly colonial – but I welcome the readers’ thoughts. Amanda, Dundee
Send new questions to nq@theguardian.com.