A surveillance system, comprising: a camera unit configured to generate a digital image of a scene at a venue visited by individuals that are either authorized or unauthorized, the authorized individuals having a respective communication device configured to send authorized data transmissions, a base station configured to receive data transmissions generated by communication devices located at said venue, said data transmissions including the authorized data transmissions, a positioning module configured to determine a position parameter of the respective communication device with respect to the base station based on a respective authorized data transmission, an image processing module configured to process the digital image for detection of one or more individuals in the digital image, and a surveillance module configured to detect presence of one or more unauthorized individuals in the digital image as a function of said one or more individuals detected by the image processing module and the or each position parameter determined by the positioning module, and the or each position parameter comprises one or more of: a distance (d1, d2) from the base station to the respective communication device within the scene, and a direction from the base station to the communication device, characterized in that the surveillance module is further configured to analyze the or each position parameter to determine an expected location of each authorized individual in the digital image and compare the expected location with a respective location in the digital image of said one or more individuals to discriminate said one or more individuals detected in the digital image into authorized and unauthorized individuals (5A, 5B). a camera unit configured to generate a digital image of a scene at a venue visited by individuals that are either authorized or unauthorized, the authorized individuals having a respective communication device configured to send authorized data transmissions, a base station configured to receive data transmissions generated by communication devices located at said venue, said data transmissions including the authorized data transmissions, a positioning module configured to determine a position parameter of the respective communication device with respect to the base station based on a respective authorized data transmission, an image processing module configured to process the digital image for detection of one or more individuals in the digital image, and a surveillance module configured to detect presence of one or more unauthorized individuals in the digital image as a function of said one or more individuals detected by the image processing module and the or each position parameter determined by the positioning module, and the or each position parameter comprises one or more of: a distance (d1, d2) from the base station to the respective communication device within the scene, and a direction from the base station to the communication device, characterized in that the surveillance module is further configured to analyze the or each position parameter to determine an expected location of each authorized individual in the digital image and compare the expected location with a respective location in the digital image of said one or more individuals to discriminate said one or more individuals detected in the digital image into authorized and unauthorized individuals (5A, 5B).