A vintage U.K. stillwater pattern (I've also seen his name spelled Willock); can also be tied with a feather wing. Notional tying sequence.
hook - Mustad 79580 #6
thread - Danville 6/0 fluoro red
butt/rib - Uni-Stretch Chinese Red
body - tinsel gold
hackle - hen hot orange
wing - calftail hot orange
Part 1
mash barb, start thread, tie in tinsel
wrap to hook point with touching turns, and back; tie off/trim
start Uni-Stretch at point, wrap to barb and back
twist Uni-Stretch tight and wrap as rib; tie off/trim
tie in (folded) hackle; wrap, tie off/trim
stroke fibers down/back, cover with thread