Firstly if you think your horse will need distracting give him some hay or something similar. Using the body brush give the tail a thorough brush. Holding it in one hand, and start at the bottom in small sections working upwards. Knots come out more easily this way and it prevents them piling up and making a big tangle of hair.
Dampen a water brush and brush the tail, this makes it easier to handle and plait. Beginning at the top take a small section of hair, one from the right, one from the left and one from the middle. Plait with them once, now take another small section of hair from the left side and add it to the left side of the plait. Cross it over to the middle of the plait. Then pick up a small section of hair from the right side of the tail and add it to the right side of the plait. Then cross it all over to the middle. Repeat this until you are three quarters of the way down his tail. Keep even and constant pressure when plaiting and always keep the plait in the centre otherwise it will come out all wonky.
Now give the dock, (the tail bone) a quick squeeze, to feel how far down you are. If you are about three quarters of the way down, start to plait the long hair, as you would to a normal plait, to the end of the tail.
With a plaiting band secure the plait, and fold the plait once underneath. Now you can tuck the end of the plait under the French plait, and secure it with your other plaiting band. Instead you can secure it by using a needle and thread with the end knotted.