In the first half of the 19th century there would have been no need for the term. Because Mild Ale was all relatively pale, being brewed from just pale base malt. Only when some Mild Ales began to darken - sometime at the end of the 19th century - would there be any need for it.
So I went out a searching. In the British Newspaper Archive and Google Books.
The latter turned up the first mention: in 1897. It's from a brewing trade magazine, so a pretty reliable source. Unfortunately, the book is only snippet view. I'm missing the context. But it unequivocably describes a beer as Dark Mild Ale:
"CHART 5.-C. Dark Mild Ale, uncoloured, equalling "B" in the 1-inch Colour units."Oldest reference in the British Newspaper Archive is from 1906. In a Fremlin's of Maidstone advert. It got me all excited. Until I looked more closely.
Journal of the Federated Institutes of Brewing, Volume 3, 1897 page 420.
|Kentish Independent - Friday 22 June 1906, page 3.|
Dark Bitter isn't as insane as it sounds. After WW I, they basically only brewed Pale Ales in Scotland. Coloured up to all sorts of different shades, including near black.
Unusual to see a Porter being brewed outside London this late. Though they were obviously selling it as Stout, when bottled. Come to think of it, the Cooper, Elephant Brand Stout and Oatmeal Stout look like they were bottled Porter, too. Based on the price.
Most unlikely appearance is Fremlin's Pilsener Lager Beer. Very few breweries produced a Lager at the time, other than specialists with dedicated Lager plants.
Most weird ids that there's just a single beer described as Mild Ale, amongst the multitude of products.