This is a slight variation on the original Cat's Whisker which was invented in 1985 by David Train.
It was then publicised widely principally by Bob Church and the rest is history.
It's one of the most deadly flies you can tie to the end of your leader, and works on floating, intermediate and sinking lines on a wide variety of waters.
Some heathen types have even been known to bag big catches fishing it static, under an indicator.
The original had bead-chain eyes and incorporated a few of the inventor's cat's whiskers as a overwing, to keep the marabou in place. Later, white bucktail was used for the same reasoning.
This is virtually unheard of now - the wings tend to be tied a little shorter than David Train's original, and the modern line of thinking is that the movement of the marabou shouldn't be impaired in any way.
My best results have come using an intermediate line in conjunction with slow, steady pulls of about 2 or 3 feet in length.
Some of the takes can be savage, so I always use 7lb+ breaking strain tippet.
Here's my favourite version of this classic. It's suitable for beginners and the wording of this SBS is intended to reflect that.
Cat's Whisker
Hook: 6-12 long shank
Thread: white (optional) or black. White Glo-thread used to finish the head
Tail: white marabou
Body: fluorescent green chenille
Collar hackle: white cock
Wing: generous spray of white marabou
Place the hook in the vice and wind the thread down the shank in touching turns to above the barb.
Pull or trim a smallish bunch of white marabou feather fibres from the quill, then trim the roots so they're even and the length you need. Remove the excess fluff from the cut end with your finger tips.
Wet the roots with saliva and tie down firmly at the bend.
Bind the fibres down well, as shown. Return the thread to the bend.
Expose the core strands from a 4-inch length of chenille and tie in.
Take the thread back up to about 3mm from the eye, then wind a body with the chenille, pushing the fibres back between each turn so the body is reasonably even.
Tie the chenille in well at the head.
Trim the chenille off neatly.
Select a cock hackle with fibres of an appropriate length. Remove the fluff from the base, any fibres which are too long, and then tie this in with 3 or 4 turns shiny (good) side facing forwards.
Take the hackle 3 or 4 times around the shank, pushing the fibres back in-between turns. Tie in well.
Carefully trim the waste end of the hackle stalk, then brush the fibres which are on top of the shank back and down as shown below.
Take a few turns of thread to hold in place.
With your right hand grip the marabou tail fibres at the length you want, then with your left, tear the fibres to the correct length, so they're all even. Don't use scissors for this, because the result looks terrible!
Tie in a generous wing as you did with the tail, but with about 50% more fibres.
Trim the waste ends up near the eye so this isn't messy later on.
Lash the fibres down and if you wish, at this stage create a neat head, whip finish and varnish.
What I now do is complete the head by using Glo-thread which I think gives a better finish.
I whip finish at the stage shown above, then change threads.
Glo-thread has strands which are inclined to "bounce" off the end of the eye, meaning you have to start again, so be very careful using the stuff.
When you have a neat, tapered head, whip finish and complete the dressing with a couple of coats of varnish.
Once dry, tear the wing fibres to length as you did for the tail.