Broadly speaking, the present techniques generally relate to a method of generating a classification machine learning, ML model comprising a base ML feature embedding model and a generative ML model for deployment to a user device and a method of using the classification ML model which has been generated. The present techniques also relate to a method of generating a training data set for training the ML generative model to improve the classification of input images, The present techniques relate to devices and systems for carrying out the methods. Advantageously, the present techniques enable class-incremental recognition of personal object classes via conditional feature-space generative modelling with near-zero forgetting.