The application of resonant magnetic perturbation fields is a promising technique to control transient heat loads due to large type-I Edge Localised Modes (ELM) in tokamaks. Previous experiments have shown that n > 4 (n is the toroidal mode number) magnetic field perturbation were able to trigger small ELMs during otherwise ELM-free H-mode phases on JFT-2M. Magnetic perturbations with n = 1 and m = 4-5 were able to increase the repetition frequency of type-III ELMs in COMPASS-D. Recent results from DIII-D using n = 3 magnetic perturbation fields have shown that type-I ELMs can be completely suppressed in collisional and collisionless plasmas. All of these experiments have in common that the applied coil systems were built into the vacuum vessel and had only a small separation to the plasma. For next-step fusion devices, such as ITER, it may not be feasible to use internal coils due to technical constraints. ELM mitigation using magnetic perturbation fields generated with external coil systems (which are further away from the plasma than coils build into the vessel) and having low toroidal mode numbers (which have less radial decay of field strength than higher n modes) needs to be explored for ITER-relevant plasma conditions with high triangularity and high beta. This paper summarizes recent experiments on the JET tokamak where it has been shown that type-I edge localised modes can be controlled by an externally generated perturbation field using a set of four Error Field Correction Coils (EFCC) which allows one to apply perturbation fields with toroidal mode numbers n = 1 or n = 2.