Moth

My wife and I did the Big Butterfly Count at the weekend but we have one moth that we could not identify. Having looked on the web at various sites I have still not found the answer. Anyone know?

The body of the moth in the above picture is about 20mm long. The moth was very active. It was hard to even follow it by eye it was constantly moving. Most of the pictures I took of it are just unidentifiable blurs.
This picture was taken at about midday on Saturday 24 July.