hello, I'm sliding in with more info!
The fall-front closures started dominating in menswear from roughly 1760s onwards, with the rise of the waistcoat tails - once you get shorter waistcoats, it was far more preferable to have a nice looking and non-bulky front on the breeches/trousers, hence the move to fall fronts. There are loads of examples of 18th century single fly trousers in the archives, here's one of my favourite pairs (so shiny and fancy!):
source: V&A collections, accession nr T.693-1913
This blog post has a scan of instructions on how to make 18th century breeches, in case anyone is curious! The bottom of the instructions also includes close ups of the frog pockets, here's photos from one of my own pairs, based on Nelson's breeches already mentioned:
source: RMG collections, accession nr UNI0021
And the way the waistband works:
It's hiding extra flaps beneath! It's definitely a more involved construction than a modern front fly, but overall I find it less fiddly to make than modern trousers.
As for the overall trouser shape, here's a visual for what early 19th century common sailor's long trousers looked like - definitely very similar to Bush's silhouette!
source: RMG collections, accession nr UNI0092
The bottom line is, Bush is wearing trousers that are kinda shapeless*, maybe ugly to a modern eye**, and perhaps something somewhat unusual for an officer, or at least one who isn't in the Arctic and in need of something more baggy and loose to put over his long johns/warm underlayers. Whether it's an intentional choice from the costuming department, a clever use of "making do" with props from another show set in a similar but slightly different time period, or a mix of both, I guess we'll never know.
The trousers themselves are still fairly historically accurate in my opinion, although perhaps an odd choice, one that definitely stands out. The longer I look at them, the more I start wondering whether they are fall fronts, just.
e x t r e m e l y w i d e.
Do you see my vision? 😂 The button in the middle wouldn't be a closure button, but instead an extra security button making sure the flap stays up where it should be instead of sagging down in the middle. You can see that kind of closure in the sailor's trousers example above. That middle button was reasonably common in fall fronts of the period from what I gather, I've seen it quite a lot (not enough to make me fight making another buttonhole for my own trousers though... 😂).
Maybe whoever meets Paul McGann next could ask him if he remembers his trousers from Hornblower, and maybe then we'll be able to shed some light on this situation, haha.
Ok, Phil out, thanks for coming to my ted talk! 💖
*please notice how they're technically the same shape as the off-white ones of the other officers, but the navy colour makes them look more like sweatpants rather than "proper" trousers. fabric was essentially up to the tailor, they'd make clothes out of what was in the shop, and if you bought from different sources you'd be unlikely to have the same shade of navy (and if Bush lost his trousers on board, he'd have to buy from the slops chest, and there would be limited options). you can see different shades on the same kinds of fabric in uniforms on display in museums, in fabric shops stocking wool and linen, and it's also easily visible in Hornblower! Pellew's jacket and Horatio's jacket are ever so slightly different in colour. I know this for normal reasons, not because I was staring at their uniforms for far longer than necessary.
**don't get me started on the modern concept of fashion and how fucked up a lot of our perception of shapes and "fit" are...
