Plymouth gin has had a bit of a chequered history but it's current owners (Pernod Ricard) seem to appreciate what they've got. It's been around for a long time (the bottle says established in 1798) has been based in the same distillery for all of that time, and is the only gin in the country to have protected geographical origin status. Plymouth gin has to come from Plymouth (unlike London gin, which is a style) since the 1880's when they (and possibly other Plymouth based distillers) took legal action against London based distilleries who were using the name.
By this time it'll come as no surprise (when I'm describing a gin I really like) to hear that Plymouth is quite juniper forward - and smooth with it. I've seen it described as less crisp, or more earthy, than London gin and can think of no better way of defining it than that so will stick with it. It's a classic, and despite sometimes wavering fortunes, has had some famous fans (Winston Churchill and Alfred Hitchcock were both keen it seems) and is specifically named several times in the Savoy cocktail book (from the 1930's). It also has a long history with the British Navy - by 1850 they were apparently buying a 1000 barrels a year.
Rum might have been the spirit dolled out to the rank and file of the navy, but gin was what the officers had (with a dash of Angostura bitters for that old standby - a pink gin, though fever tree now do an angostura bark infused tonic which is handy). It's an association that seems miles away from the 'drunk for a penny, dead drunk for tuppence, clean straw for free' imagery of the gin craze of the 18th century, or the Mrs Gamp style Victorian tipplers that Dickens gave us - or even the tawdry glamour of the gin palaces. The truth may not have been so very different back in the early part of the 19th century but I want to dream of adventure on the high seas Patrick O'Brian style, though if this was gin and films it would be 'In Which we Serve' with Noel Coward, and if I find myself reading any WW2 boat based thriller it would have to be Plymouth gin with that too.
I bet Jane Austen's Captain Wentworth liked a Plymouth gin as well...