Mystery white flower

[davidbr]

Does anyone have any idea what this is? It's a low-growing plant amongst short grass, just coming into flower, and I'm assuming it's probably a native - although the site (Sand Bay, Somerset) is well-known for all kinds of unusual aliens & escapes.

The flower suggests some kind of sandwort or pearlwort, but I can't seem to find one that matches.

[treecreeper]

I think it might be fairy flax, linum catharticum

[KeenTeen17]

I think it might just be a fairy flax Linum catharticum that hasn't fully opened yet. The leaves look right and so do the habitats you stated.
Fairy Flax (Linum catharticum)

[davidbr]

You know, I'd never even considered that - I was so convinced it was a member of the Pink family that I didn't bother to look elsewhere

Having checked some more pictures it's definitely Fairy Flax - thanks to you both for your help

[JennyS]

Its very early flowering if it is .....