Danish label Ganni and British rainwear institution Hunter have teamed up for autumn, and while the leopard-print wellies and fisherman hats are grabbing the headlines, the sleeper hit of the collection might be the cheapest thing in it: a £50 water-repellent coat designed specifically to slip over your handbag.

The idea sounds gimmicky until you picture the scenario it solves. You're on a European city break between September and December, the forecast is indecisive, and your leather shoulder bag is getting soaked while you dash between museums and coffee stops. The cover is cut to fit Ganni's own Mini Bou and Small Bou bags, but it works beyond the family too. The handle opening measures 17cm, so it slips over plenty of everyday bags, and at 75cm wide with a 30cm drop it drapes over small shoulder bags and top-handle styles, adapting its shape to whatever sits underneath.

For travellers, the packing argument is arguably the strongest one. The clear cover folds down flat and adds virtually no weight across the top of a carry-on, so there's no agonising over whether to bring it. If the sun shows up, you've lost nothing; if the skies open, your bag stays dry.

There is one honest caveat: this is water-resistant, not waterproof. It will handle intermittent showers and wet sprints across a square in Copenhagen, Venice or Paris, but it's not kit for a hill walk in the Scottish Highlands or a soggy week in rural Ireland. Think urban drizzle, not proper weather. Expect it to show up all over street-style photography during fashion month in Milan, London and Paris too, if that's the sort of crowd you like to blend into.

Who is this actually for? Anyone who carries a nice bag and refuses to let a bit of rain dictate their itinerary — so, most people heading on an autumn city break. It's also a low-stakes way into the Ganni x Hunter collaboration, which otherwise centres on pricier raincoats, boots and hats in Hunter's classic shapes given Ganni's animal-print treatment. At £50, it's the most affordable piece in the range, and it doubles as a fun bit of dressing-up even if you don't own a bag it was designed for.

It won't replace a decent rain jacket, and nobody needs it in the strictest sense. But as far as packing-list whims go, this one earns its slot: featherlight, flat-folding, genuinely useful for the grey months, and more charming than a plastic bag pulled over a handbag at a tram stop — which, let's be honest, is the alternative.