A device for chocking and retaining a dovetail root of a blade of a gas turbine engine in a corresponding axially-extending slot in the rim of a disc, the root being mounted in the slot by insertion of a leading end of the root into a proximal end of the slot and then sliding the root towards a distal end of the slot. The device includes a first wedging body having a key portion receivable in a keyway formed at the distal end of the slot. The keyway restrains the first wedging body against movement in the axial direction. The first wedging body further has a first angled surface over which a correspondingly angled leading end surface of the root slides when the root is inserted in the slot to urge the leading end of the root radially outwardly.