Giant elms play an important role in controlling the divertor tokamak edge plasma and cause the loss of a substantial fraction of the plasma energy and particles over a short time interval of ~100ms. This leads to a very high power loading of parts of the tokamak wall structure. The details of the loss processes are not understood. Using a set of highly time-resolved diagnostics, the flow of both energy and particles during giant Edge Localised Modes (ELMs) has been determined for the first time. The soft X-ray measurements show a very rapid onset of the instability and have a remarkably complex structure. They prove that the plasma energy is deposited both in the divertor and other areas of the vessel, and that of the particles lost, many are recycled to well within the separatrix. The implications of the measurements for the elm instability mechanism and the design of tokamaks are discussed.