Abstract: A capacitive sensor for mounting to a body, particularly a body such as a van door (55). The sensor has a sensor plate (51) to which a first signal is applied. A first guard plate (52) is interposed between the sensor plate (51) and the body (55), and a second guard plate (53) is interposed between the first guard plate (52) and the body (55). The first and second guard plates (52, 53) each have signals applied thereto which are the same or at least similar to the first signal applied to the sensor plate (51). In this way, the second guard plate (53) acts as a rear guard to the first guard (52) and reduces its capacitance to ground. This reduces the current drawn by the first guard (52), allowing it to more accurately track the signal on the sensor and consequently better mask the sensor plate (51) from the body (55).