At first I though Leucojum vernum var. carpathicum but on looking again I think it is a Galanthus, one with a green tip to the outer 'petals'.

I would say exactly as Owdboggy. The flowers don't seem to be quite 'chunky' enough for Leucojum.

I think it is a Leucojum as it looks as if it is on a longer stem and is a fresh green whereas snowdrops are shorter and the leaves are more of a grey/green.

Easy way to tell, in Leucojum all the petals are the same length ,in a Galanthus the three inner petals are shorter than the outer ones. Also the 6 petals would be tipped with green in Leucojum. In Galanthus the inner petals would have a horseshoe shaped mark. There are Galanthus with pure green leaves.

It looks exactly the same as a long-stemmed plant I have that came from my mother's garden many years ago. She always called it 'snowflake'. By the photo and the descriptions given, I would guess it is a Leucojum.

So it's a snowflake rather than a snowbell or snowdrop! I almost got it right ;)
Thanks everyone