It's certainly looks like Alium ursinum, Wild Garlic. It's native here and I have it in my garden. But it is a bit of a spreading menace. Highly edible.

It looks like you got it, linaria and floraluk! The description matches, including the triangular flowering stem, and the occurence of both leaves and flowers at the same time. I have no idea how it got here. We have something similar in eastern Canada and the US, Allium tricoccum, but that blooms after the leaves have died down, in June or July, it seems. It common name is ramps, this is called rampons, I read. It has not moved or produced seedlings in at least three years, as far as I can see. Thanks for the warning about its rampageous tendencies. If I notice more, in the pot they go! Maybe even this one plant will end up there next year. Now it is probably tough and stringy, it is starting to die down.

Ramsons here. Never heard of Rampons. You can chew the base of the flower stems even after they've gone to seed and the leaves have died off. A woodland walk snack.

I make pesto from the leaves when they're young and fresh. Also cook with it.

You are right: ramsons! New word for me…

I will see how much I can harvest, without things getting out of hand ;-).

They were called rampons before the Vikings conquered.

I didn't say they weren't, just that I'd never heard that name for this Allium. Nor has Google or Wikipedia. Afaik Rampons is a French common name for Valerianella locusta. There's also Rampion, Campanula rapunculus.

ps The green seeds make a tasty sprinkle in a salad.

It was a joke about surnames. The leaves ransoms look thicker than our ramps. We have 2 native species in the east, Allium tricoccum and the rarer Allium burdickii. Are the American ramps grown in England? Can you describe the taste of ramsons? oniony, garlicky? Mild? Celebrity chefs are helping put our native ramps on the endangered list. I've never grown them successfully from seed.😟

Ramsons taste very oniony, like a very strong chive. But the flavour becomes mild when they're cooked.

The flowers are over in my garden, where they are a prolific 'weed'. It's raining at the moment. As you can see the snails are out in force.

I don't know if anyone grows the American species. But we do have the invasive A triquetrum spreading here.

The snails don't like ramsons? You could make ramson snail repellent? I had a similar problem with pillbugs, isopods years ago. They came out at night a defoliated some olants. It was mostly the newly planted marigolds. Starlings would steal whole marigold plants. I don't grow marigolds anywhere.

Well, they don't eat them much but they're happy to crawl all over them to reach stuff they like, so not much of a repellent

On the first picture I spot one of those huge brown slugs too? My mom (in the Netherlands) hated those. She said they got so large, you could cook soup with them. An idea? Slug soup with ramsons 🤪!

Yup. All kinds of gastropods. Some are scavengers and do no harm but sadly I can't tell which ones.

I didn’t know there are harmless ones? I remember once being in the Netherlands in October, when one morning after a night's rain the sidewalk of my friend's house was so full of those 2"+ brown ones, you could hardly walk without stepping on one. I am quite happy where I am now, no slugs or snails to speak of. But long, cold winters… You cannot win.

Patch of ramps (Allium tricoccum) near me, spreading out from a long-ago few transplants by a neighbor. Mild onion flavor of the young leaves, good to stir-fry w/potatoes.