Cross machine identity experiments have been performed on JET, DIII-D and ASDEX Upgrade to measure the physics governing Neoclassical Tearing Mode (NTM) metastability and its scaling towards ITER. Results indicate ITER baseline scenarios will operate well above the b threshold for metastability of NTMs, and so be susceptible to NTM triggering events. Modelling techniques have been extended to use a fully time dependent treatment, with local parameters and a full bootstrap calculation in order to reproduce detailed island evolutions, responding to changes in profiles. Preliminary results indicate a weak scaling of scale length associated with small island size stabilisation effects, indicating that for complete removal of NTMs in ITER, ECCD systems will have to drive islands down to a few cm in size, similar to levels required for mode removal in present devices.