Under the terms of the order, according to the Assistant State Secretary for Internal Administration, Maria Isabel Oneto, in line with data protection legisilation, hidden cameras cannot be installed and those that are part of the video surveillance system, “should be directed so as not to capture images in more reserved locations of prayer, such as the inside of churches, chapels and devotional areas.”

Sound may be recorded “whenever a concrete situation is found to be a danger to people and assets,” and "private locations are barred, preventing the observation of doors, windows and balconies,” the order noted.

The cameras will operate around the clock and the system will be managed by the Tomar GNR police.

Pope Francis is due to travel to Fatima on 12 and 13 May for the centenary celebrations of the Fatima apparitions