ABSTRACT. The database on runaway electrons (RE) collected in JET with carbon-fibre composite tiles in plasma facing components (PFC) (JET-C) has been complemented by recent results of experiments on disruptions and RE generation in JET with full-metal ITER-like wall (JET-ILW). New experiments with Massive Gas Injection (MGI) provided conditions for predictable RE generation in disruptions. In these studies the RE generation process has been mapped in ranges on toroidal magnetic field, pre-disruption plasma density and fraction of argon used in mixture with deuterium (10÷100%) in MGI for future RE suppression experiments. New results on RE generation trends and disruption physics have been obtained. A significant extension of RE generation boundary to the lower magnetic fields (up to 1T) was found. RE current (up to 100kA) has been measured already at 1.2T. Temporal and spatial dynamics of RE beams have been studied using measured hard and soft X-rays emissions during RE stage. Energy spectra of RE have been measured. Data is used to contribute into the model of RE generation in the presence of spatial dynamics of current carrying channel and to the analysis of the interaction of RE beams with PFC.