Abstract: The invention relates to an initiating element for use in a detonator to cause a base charge arranged in the detonator, to detonate. The initiating element comprises an ignitable initiating charge which upon ignition generates combustion gases by means of which the base charge is intended to be caused to detonate. The initiating element comprises a compression means which is arranged to be acted upon by said combustion gases to be moved towards the base charge for compression of the same. The invention further relates to a method of igniting a compressed base charge in a detonator, the base charge being further compressed during an initiation phase to increased density. In addition, the invention relates to a detonator provided with a base charge which at a moment of detonation has increased density.