To ensure sufficient divertor target lifetime, the loss in plasma stored energy due to ELMs in ITER should be restricted to DWELM ~ 1 MJ. Only in JET, by virtue of its size, can such energies be approached. This contribution examines the impact of large ELMs in high current H-mode JET discharges with ITER-relevant pedestal characteristics and the carbon MarkIISRP and HD divertors. The ELMs provoke strong radiation losses, mostly confined to the inner divertor volume, which are generally ~0.5DWELM, but which can reach ~0.7DWELM for the largest DWELM, indicating enhanced impurity release. Peak divertor target surface temperatures are too low for carbon sublimation, suggesting that thermal decomposition and/or ablation of thick co-deposited layers on the inner target may be occurring. The largest ELMs deposit on average ~10% of DWELM on main wall surfaces, an energy fraction which is well reproduced by a model of ELM filament parallel energy losses developed at JET. Preprint of Paper to be submitted for publication in Proceedings of the 18th Plasma Surface Interactions in Controlled Fusion Devices Toledo, Spain ( 26th May 2008 - 30th May 2008)