So effective; so simple... it makes you wonder why we bother with the more complex patterns
Perfect for grayling:
If you own some Chadwicks 477, then use it! If not, search for a substitute that gives you confidence.
Hook: Your Choice (This is a Varivas 2120WB #14)
Thread: Copper wire
Yarn: 477 (or substitute)
Catch in the copper wire
Wind a base layer of the wire with finishing near the bend of the hook
Catch in the yarn
Bind down the yarn and return the wire to the bend of the hook.

(You can add more wire to achieve greater depth here)
Wind the yarn up and back. Try to achieve a taper at each end.
Whip finish at the bend and add a drop of varnish
Also worth trying with pink wire:
More here:
Tying the Killer Bug
~Dave