I don't recognise it - if someone else does, all well and good, but if they don't, please post a photograph of the actual plant to show growth habit and foliage.

Hi Annie and welcome to Goy. Phacelia, used as a green manure, and much loved by bees I'd view it as a 'wild flower' rather than a weed to be pulled up.

Ah! Not the Phacelia I know, this one's Phacelia tanacetifolia, the only one I've ever grown/seen is P. grandiflora (also loved by bees!)

What an unusual flower, it looks as though it's been knitted.

You can buy it as seed in most garden centres, or even in quantity packs for use as green manure. Some of the farmers round here (Norfolk) have sown this as 'set-aside' for the insects.