"Most gin in this country is drunk with tonic and ice and lemon. And, if you want to take trouble, a squeeze of fresh lemon juice. After many years of exposure, I find this a rather unworthy, mawkish drink, best left to women, youngsters and whisky distillers. Its history is suspect: in the days of the Empire, you were supposed to drink quinine water, the ancestor of tonic, to keep away fever. Someone noticed that the vile stuff went down a little better if you splashed gin into it. What an idea!
One large gin and tonic is acceptable as a thirst quencher.[…]
For further, serious drinking I recommend gin and water- and ice and lemon. This combination is favoured by the understandably popular George Gale. My advice: make sure you don’t overdo the water. Gin and water is an all-round improvement on gin and tonic: cheaper, less fattening and less filling as well as being not sweet or gassy. Gin is a real and interesting drink, carefully prepared with those botanicals and all, and it deserves to be sampled with its flavour unimpaired…"
(Kingsley Amis, Everyday Drinking, p.104 f.)
I find this completely acceptable also with mineral water, too. We in Austria have some excellent mineral waters by the way...and they also have a certain cachet since they are not widely known.