An original spot detection method for large surveys of videos in JET is presented. The method can be used for the automatic identification of spots in JET IR videos and for the assessment of the long term trends in their evolution. This method has been applied to the analysis of a large database of JET IR images collected during the last campaigns of operation with the ILW. The evolution of the spots and their properties, such as size and distribution, can be correlated with macroscopic events, in particular series of intentional disruptions. On the other hand, care must be taken in the interpretation of the results since there is some evidence of toroidal asymmetries in the spot distribution.