In Fleming's left hand rule, which finger signifies the direction of force?

In Fleming's left-hand rule, the thumb signifies the direction of force. 

Fleming's left-hand rule, when a current-carrying conductor is placed in a magnetic field, it experiences a force. 

Fleming's left-hand rule can be used to identify the direction of the force. Where the forefinger represents the magnetic field direction, the middle finger indicates the direction of current in the conductor and the thumb shows the direction of the force exerted on the conductor.