Abstract: This invention relates to a method or apparatus for provision of display screens. Display screens used in remote locations such as those as may be used for billboards etc. run the risk of tampering or interference with the data supplied to the screens for display. This may particularly be preferment with billboards controlled by the worldwide web. The invention sets out methods of verifying the content to be displayed on the screen including checking the incoming data feed or checking the actual image displayed on the screen. In addition, the invention provides various methods of monitoring the performance of the screen to verify the images being displayed and to adjust for degradation of display components or otherwise monitor the performance of the display.