Postboxes are hugely convenient tools for helping us get our letters and cards sent across the country without having to travel all the way to a proper post office.
But while millions of us make use of the Royal Mail's little red pillars every day, have you ever stopped to take a look at the markings on the front of the box?
Each postbox comes with a symbol printed underneath the letter slot, and while the origins of that symbol might seem obvious to some, others are only just realising what it means - and it has a rather interesting history.
