Dragonfly nymph

Ever since I spotted the dragonfly exuvia a few days ago, I've been on the lookout for another.  Today, I spotted this. 

First seen at 4.40 (the clock on my camera is still on GMT), I had to go out to fetch W, but when I got back at 6.00, it was still unchanged.  I don't think the dragonfly has managed to emerge, and I fear it is now too late.  I'll check it again before it gets dark, but I hope it waits till the morning, so I can pop down there when I get up, before going to work.