Abstract: An electrically conductive security screen includes an electrical resistance sensor and alarm to detect tampering with the screening material of a window. An elongated path of flexible and electrically conductive coating composition is applied to the screening material in a predetermined and non-overlapping pattern, such that a closed circuit loop is formed when it is attached to the sensor alarm; the coating having an electrical resistance that varies when it is distorted or its path interrupted. The pattern having a marginal section of high electrical resistance and being in series with at least one switch.