We present the results of numerical simulations of the buoyant rise of the cocoons of radio galaxies after they come into pressure equilibrium with the surrounding gas. As in the later stages of nuclear explosions, they evolve into rising tori which can uplift dense, cold gas from the cluster centre. We also calculate the expected radio emission from these structures and suggest that this may explain the 'ears' observed in the large scale radio structure of M 87. Finally, the plasma will reac...