A modular deployable display unit (412,512) including: a flexible electronic display member (428, 528) which is configured to display a programmable message, the flexible electronic display member (428, 528) being displaceable between: a deployed configuration wherein the flexible electronic display member (428, 528) extends outwardly for displaying the programmable message; and a stowed configuration wherein the flexible electronic display member (428, 528) takes up a relatively compact configuration; at least one electrical cable (430, 530) for supplying electrical energy to the flexible electronic display member (428, 528); and connecting means including connecting formations (434.1, 434.2, 534.1, 534.2) for physically releasably connecting the modular deployable display unit (412, 512) to an additional modular deployable display unit, in an end to end arrangement; characterized in that the flexible electronic display member (428, 528) in the deployed configuration at a scene is configured for completely blocking a view of the scene; wherein the flexible electronic display member (428, 528) includes one or more inflatable bodies (453, 552) for displacing the flexible electronic display member (428, 528) into the deployed configuration, the flexible electronic display member (428, 528) defines a plurality of apertures (454, 554) defined therethrough for permitting the passage of air through the plurality of apertures (454, 554), and wherein the flexible electronic display member (428, 528) includes a plurality of flap members (457, 557) each associated with a particular one or more of the apertures (454, 554) and each arranged to cover the associated one or more of the apertures (454, 554). a flexible electronic display member (428, 528) which is configured to display a programmable message, the flexible electronic display member (428, 528) being displaceable between: a deployed configuration wherein the flexible electronic display member (428, 528) extends outwardly for displaying the programmable message; and a stowed configuration wherein the flexible electronic display member (428, 528) takes up a relatively compact configuration; at least one electrical cable (430, 530) for supplying electrical energy to the flexible electronic display member (428, 528); and connecting means including connecting formations (434.1, 434.2, 534.1, 534.2) for physically releasably connecting the modular deployable display unit (412, 512) to an additional modular deployable display unit, in an end to end arrangement; a deployed configuration wherein the flexible electronic display member (428, 528) extends outwardly for displaying the programmable message; and a stowed configuration wherein the flexible electronic display member (428, 528) takes up a relatively compact configuration; at least one electrical cable (430, 530) for supplying electrical energy to the flexible electronic display member (428, 528); and connecting means including connecting formations (434.1, 434.2, 534.1, 534.2) for physically releasably connecting the modular deployable display unit (412, 512) to an additional modular deployable display unit, in an end to end arrangement; characterized in that the flexible electronic display member (428, 528) in the deployed configuration at a scene is configured for completely blocking a view of the scene;