Its difficult to be 100% sure on this but I believe this is something much much better than a Pale Tussock. This looks from this angle like Clifden Nonpareil Catocala fraxini also known as Blue Underwing. Did you happen to give it a tickle to see the underwing? Where roughly are you located and out of curiosity when was this taken?
Very interesting and if I were you I would send this photo and any others you have of it into your county moth recorder to see what they think. Nice rare migrant.
Thank you very much for your interesting reply! Unfortunately I only got two shots of it, the second is attached below and doesn't show much more than the first. As I was maneouvering around to get a different angle it flew off and as I was focusing the camera at that time I missed the view of its underside!!
It was seen today (10/09/12) at 10:47am. It was actually sat on some trellisin my garden in full/bright sunshine! I'm in North Somerset half way between Bristol & Weston-Super-Mare roughly.
Hope that helps?
How would I go about finding my county Moth recorder?
Well I think it is mostly likely Clifden Nonparell but you should send these in to the county recorder. You can find his name (for anyone in any county looking at this) from here: MothsCount Website, every county has one.
Yours for Somerset is on the pdf file on that page. He will be most pleased to hear from you I am sure!
From what I've read these are most seen in eastern and southern UK, we've had records near me but I've yet to see one (I'm very jealous ). Well done getting photos.
EDIT: Have just seen your reply post, thats a shame, They are similar and even from underneath could have clinched it. Our county recorders have to be spot on or the records become tarnished with 'we think's and 'probably's so I understand. I still suspect Clifend Nonpareil
It's a real shame that I didn't see the underwings but that often happens when trying to get in close for a picture you sometimes miss the 'key' moment!
I do really appreciate all your input, as you will have noticed I'm on a massive learning curve here so will take on board anything that you throw at me!!
At least I now know what to look for next time!!... :-)