I have it as Grey Birch, Aethalura punctucata, the local habitat is correct but it is a bit early (photographed this morning).
[attachimg=1]
After looking through my book I would agree with that.
Looks like it;
http://ukmoths.org.uk/show.php?bf=1951 (http://ukmoths.org.uk/show.php?bf=1951)
http://www.northumberlandmoths.org.uk/admin/getthumbs.php?id=413 (http://www.northumberlandmoths.org.uk/admin/getthumbs.php?id=413)
TL
MC
This is nice with good colour plates;
http://archive.org/stream/britisheuropeanb00kapp#page/24/mode/2up (http://archive.org/stream/britisheuropeanb00kapp#page/24/mode/2up)
archive.org/details/britisheuropeanb00kapp (http://archive.org/details/britisheuropeanb00kapp)
TL
MC
We get them about, we are surrounded by birch, but not usually until the birch leaves are out and the are only just starting.
The warm spell at the end of March must have brought them forward.