An injection device comprises a locking mechanism between a syringe carrier (127, figure 3) and a drive mechanism (129, figure 3) of the injection device. The syringe carrier is connected to a latch actuator 137a from which locking arms 171 extend to engage a locking surface 172 on the drive mechanism, such that the syringe carrier can not be moved forward without corresponding forward motion of the drive mechanism. The drive is secured in place by a locking trigger arrangement (102, figure 2a) which bears on the housing of the device. Only when the trigger is released can the drive operate and so move the syringe carrier into its operational position.
