I'm frankly useless at wild plants, so perhaps the assembled masses can tell me, what is this white flower seen in a grassy field in Norfolk (in the grounds of Felbrigg Hall to be precise)?

Update: Mike sent in a comment that gives an answer – "This unusual white flower is called Star of Bethlehem (Ornithogalum Umbellatum – Liliacae). There should be a green stripe on the underside of the petal. It is unusual in the way that it has what look like smaller white petals surrounding the yellow Anthers.