Clearance
Post boxes are emptied ("cleared") at times usually listed on the box in a TOC, Times of Collection, plate affixed to the box.
Since 2005, most British post boxes have had the time of only the last collection of the day listed on the box, with no indication of whether the box is cleared at other times earlier in the day. The reason given for this by the Royal Mail is that they needed to increase the font size of the wording on the "plate" listing the collection times to improve legibility for those with poor sight and that consequently there was insufficient room for listing all collection times throughout the day. The "Next Collection" tablet, where fitted, was usually retained in these cases, but tablets now merely show the day of the week, indicating whether or not the last collection has been cleared that day.
Read more about this topic: Pillar Box