Electron heat pulse propagation in JET H-mode and ITB plasmas was analysed using the TRANSP code and ECE measured electron temperature. The heat pulse caused by ELMs in standard H-mode and hybrid scenario discharges propagate in accordance with the Critical Gradient Model (CGM). The electron temperature profile stiffness is typically observed in the plasma above criticality in the outer half of the plasma radius and disappears in the core. The analysis allows determination of the critical value of R/LTe and the stiffness factor. The theoretical predictions based on the trapped electron mode model were compared with the experimentally deduced parameter R/LTe. Electron temperature profile stiffness factor was found to be of the order of one in the outer half of the plasma radius and decreasing in the core. The same technique has been applied to ITB plasmas. The critical gradient model is inapplicable for description of electron heat flux variations inside ITB caused by large type-I ELMs. Temperature perturbations are strongly damped inside an ITB. The CGM can be applied in the region between ITB and the plasma periphery. The stiffness factor deduced from experimental data are close to or slightly above of what is observed in standard H-mode plasma.