The nature of the radially spreading flow that forms after a vertical buoyant jet impinges on the surface has been investigated. Previous studies have provided conflicting conclusions as to whether or not an internal hydraulic jump forms in the radially spreading flow. Experiments by various investigators have been examined The radial flow initially behaves like a buoyant surface jet whose thickness increases linearis due to the entrainment of ambient fluid into the jet via shear instabilities. Eventually, buoyancy forces dominate and these instabilities collapse leaving a radial buoyant plume of almost constant thickness. Visualisations of the experiments provide no compelling reason to postulate ihe existence of an internal hydraulic jump.