JET divertor load measurements using embedded thermocouples have indicated a large target asymmetry and non-uniformities in the loads and that, under H-mode conditions, the load is dominated by the ion component. ASCOT simulations of the ion contribution to JET divertor loads are consistent with the presence of a large outward radial electric field Er in the Scrape-Off-Layer (SOL) next to the separatrix. Such a field would provide an explanation for observed features of the divertor loads in JET. The required field for reversing the load asymmetry is within the range of the estimated SOL Er in JET, but reproducing the experimental heat deposition profiles requires higher field values.