A coupling device for coupling a first vehicle to a second towed vehicle, the coupling device including a pillar (3) for mounting to a towbar attached to the first vehicle; a connector (30) for connection to the second towed vehicle; a sleeve (13) linked to the connector (30) and adapted for engagement with the pillar (3) by fitting over the pillar (3); and a collar (15) adapted to fit over and engage with a portion of the sleeve (13) for movement with respect to the sleeve (13); wherein the collar (15) is movable with respect to the sleeve (13) between a first unlocked position in which the sleeve (13) is removable from the pillar (3) and a second locked position in which the sleeve (13) is not removable from the pillar (3).