Slice is created by the racquet head brushing down the back of the ball.
The spin creates a lower, flatter trajectory over the net and makes the ball stay low off the bounce.
Henman uses his backhand slice to approach the net; the spin keeps the ball low forcing his opponents to hit up giving him an easier volley.
The Williams sisters use the backhand slice as a defensive shot when stretched out wide.
It is easier to play on the stretch and again the low bounce will make it more difficult for opponents to attack.
As with all the groundstrokes the key is in the preparation.
For the backhand slice you need to use the continental grip. To find this put the V between your thumb and index finger on the edge of your racquet's frame.
Then slide your hand down the frame to the grip - this will be the correct grip.
Your spare hand should be holding the racquet lightly at the throat.
From your ready position turn both hands and your trunk to the side so that the shoulder of your hitting arm is pointing to the ball.
As you turn to your backhand, the shot starts to differ from the top spin.
The moment that you see the ball heading to your backhand take the racquet back by turning your shoulders.
As you turn, bring the racquet head up high with your non-hitting hand, almost bringing the racquet strings behind your head.
As you get in position load the weight onto your back foot and then as the ball starts to arrive transfer the weight onto the front foot and lean into the shot.
The racquet swing should be a knifing action down from high to low grating the racquet strings down the back of the ball - this should really make the ball fizz with all the backspin.
Try to add to the high to low swing by extending the racquet head out through the ball towards the target.
Feel your spare hand extend out behind you as a counter balance to the forwards swing.