When a bed of particles is fluidised by a liquid, it is commonly observed that the velocity is not uniform, and channels form readily. Once a channel forms, it destabilises the bed because it creates a path of lower resistance than the bed itself, and liquid is drawn from the surroundings. Parts of the bed are not fluidised at all, so the bed height is lower than expected. It has been found that when an agitator such as a Rushton turbine is placed in the bed, the impeller has a beneficial effect on its stability. At low speeds, there is a marked reduction in channelling, and the energy imparted to the bed is dissipated entirely within the bed. As the rotational speed increases, the bed height increases also, indicating that the fluidising liquid is being distributed uniformly. Beyond a certain speed, the effect of the impeller can be seen at the top of the bed. Measurements are presented of the power consumption as a function of the impeller rotational speed, the impeller position within the bed, and the ratio of the liquid superficial velocity to the minimum fluidisation velocity.