The present invention relates to a medicament delivery device comprising a generally elongated housing (10 100 102) a drive assembly disposed in said hosing and an actuation assembly operably connected to said drive assembly wherein said drive assembly comprises a guard member (12 104) and an actuator member (44 180) characterised in that the actuation assembly further comprises a locking member (28 32) disposed between the guard member and the actuator member wherein said locking member is configured to be moved by the guard member when the guard member is pressed against a delivery site between a first locking position in which the locking member is blocking the actuator member and a released position in which the locking member allows the actuator member to be operated.