Reliable physics-based extrapolation of the Edge Localized Modes (ELM) heat loads to ITER requires a better understanding of the physics mechanisms that determine the dynamics of the collapse of the plasma pedestal. Fast Electron Cyclotron Emission (ECE) radiometry allows a space resolved study of the dynamic behaviour of the ELMs. In the present work, we extend previous studies of the ELM dynamics carried out in JET [1] by including simultaneous ECE measurements in the outboard (Low-Field Side or LFS) and the inboard (High-Field Side or HFS) midplane. This is possible in JET because the existing ECE heterodyne radiometer can be set up to measure simultaneously 1st harmonic/O-mode and 2nd harmonic/X-mode radiation [2]. Access to the plasma HFS is obtained by using O-mode polarization, which is not affected by harmonic overlap, while the X-mode polarization is used to measure the LFS temperature profile. This allows comparing, for the first time, the electron temperature (Te) crash caused by type I ELMs in both the inboard and outboard midplanes in JET. Simultaneous LFS and HFS Te pedestal measurements can be only achieved for a subset of the available magnetic fields values at JET. Most of our measurements have been collected in experiments with Beta0 = 2.4T and 2.7T, and Ip from 1.7MA to 2.5MA (4.9 <q95 <3.3). For the study presented here we have built a database of discharges with dominant Neutral Beam heating (PNBI~10-22MW) and reproducible type I ELMs, covering a wide range of pedestal plasma parameters (Te,ped = 0.5-1.8keV and ne,ped = 2-8x1019 m-3). The range of average triangularity in the database goes from 0.36 to 0.42.