Detailed disruption related studies have been undertaken at JET in 2001-3. An enhanced halo current detection system has allowed more precise halo asymmetry measurements to be made, confirming the assumptions in the ITER design guidelines. The runaway electron database has been systematically analysed and self­consistent simulations are underway. Disruption heat deposition, which is of fundamental importance for ITER, has been investigated and in JET it has been found that normally only a small fraction of the thermal energy goes to the divertor during the whole disruption. In addition, some energy has been observed on the outer wall at the thermal quench. The neutral point has been experimentally found and a plasma control model has been used to reproduce the dedicated discharges. Helium, neon and argon puffs have been applied as disruption mitigation techniques in JET following the success of recent studies in ASDEX Upgrade, TEXTOR and DIII-D.