A fault indicator for a strip advancement mechanism comprising a base that defines a fault sensing portion of a path for at least a component of a strip, an element for bearing against a strip, or a component of the strip, while it passes through the fault sensing portion of the path, wherein the element is adapted to move from that bearing or non-fault position, to a fault indicating position in the event of the strip or the component of the strip ceasing to pass through the fault sensing portion of the path.