Polyporus Squamosus

Just in case you think I've become a leading authority on fungi, I can reassure you that identifying it took 15 mins of internet trawling. Also garnered the following info:
Polyporus squamosus is a bracket fungus, with common names including Dryad's saddle and Pheasant's back mushroom. It has a widespread distribution, being found in North America, Australia, Asia, and Europe, where it causes a white rot in the heartwood of living and dead hardwood trees. The name "Dryad's saddle" refers to creatures in Greek mythology called Dryads who could conceivably fit and ride on this mushroom, whereas the pheasant's back analogy derives from the pattern of colors on the bracket matching that of a pheasant's back.
So now you know!
Watched American Hustle last night which was good value, not least because of the nostalgic 70's soundtrack, including thisclassic.