The reaction of a model reactive armour to a jet attack was studied as well experimentally as theoretically. An analysis of the process of driving metal plates of the armour by the gaseous products of the detonation initiated in a confined layer of an explosive by the jet at various incidence angles was performed. The X-ray impulse photography was applied to record the motion of plates at two perpendicular directions. The theoretical analysis was performed by using a simple model, in which the plate deformation and finite time of its acceleration were taken into account. The time-space characteristics of the motion of model reactive armour elements obtained from experiments and numerical modelling can be applied for designing cumulative heads destined for destroying armours protected by reactive armour.