As I sit on a train, having realised that Michael Fish got it wrong yesterday and that my four mile pootle on the Brompton at the other end will actually be in the rain, it looks like I’m going to have to get some nice new Peanuts Vans wetter and dirtier than I’d like. (Yes, I do have guards and a big flap, but my well-used Skulls-and-Feathers Vans are testament to the fact that these are never entirely effective.)
When I ride to the station and leave the bike there, I just wear old shoes if it’s wet and leave them in the panniers, but on the Brompton that’d mean carrying a pair of shoes with me, which isn’t going to happen. Whereas stuffing a thin pair of overshoes into my bag would be fine.
So… are there such things as overshoes for normal shoes and pedals? Never seen any. Just to keep the muck off, like; they needn’t be warm. Preferably not too aesthetically challenging, though 🙂
Turns out when I arrived (a) it had stopped raining and (b) I bumped into a colleague who was getting a taxi anyway 😀
Anyhoo… it occurred to me that “spats” was the word I should be searching for. But they all seem to be knee-length, not ankle length…
Loads of gaiters available to do the same job as spats would. They'd certainly help with stopping water getting on your socks and In the top of your shoes. The effectiveness of shoe covers will be dictated by how rigid you shoes are. Too flexy and they'll just keep popping off the toe.

Runners ankle gaiters like this
https://www.activinstinct.co.uk/product/black-inov-8-all-terrain-gaiter/077919_activinstinctuk/
Moar!
https://runnerclick.com/best-trail-running-gaiters-reviewed/
Those gaiters appear to cover the exact area that isn’t a pair of Vans 🙂
Bags had occurred to me, but see the final point of the original post 😉
ive got some altura covers that work well, but they're the size of wellies and make my shoes look ortho-flashy
similar to these
https://www.surfdome.com/altura_over_shoes_-_altura_night_vision_city_overshoe_-_black-166099
EDIT: actually these ones
looks like they dont make them anymore quite like that. Not a bad thing as that toe box was a pain in the bits
Vaude bike gaiters? They have long or short versions. https://www.vaude.com/en-GB/Products/Eco-Materials/Eco-friendly-Water-Resistance/Bike-Gaiter-short
Endura overshoes for flat pedals.
https://www.endurasport.com/product/mt500-plus-overshoe/
They look like overshoes, but the point is they keep your feet dry, and it’s not a fashion show.
Leave some 'normal' shoes at work, and wear some shoes that can cope with the weather, for riding in.
I might actually have a pair of those Altura ones (assuming that I didn't chuck them out) that I never quite got on with. They're fine for what they do but ended up with SPD shoes and proper overshoes. Yours if I can find them.
Another option (but not waterproof) might be a large pair of Belgian booties?
What you really want are galoshes
https://www.amazon.co.uk/McKenna-Modern-Galosh-Overshoe-6-5-7-5-x/dp/B006K0S02Y/ref=sr_1_27?ie=UTF8
A colleague uses those Altura ones with normal work shoes, he reckons they're fine.
Decathlon do over-trousers with built in shoe covers. Do the job for me.
https://www.decathlon.co.uk/100-waterproof-urban-cycling-overtrousers-black-id_8328693.html