Every president since Ronald Reagan has left a note for his successor, and President Biden could be the first to write a letter to someone who is both his successor and the predecessor who left a note for him.

US President Donald Trump has shared the contents of a letter that his predecessor Joe Biden left in his Oval Office desk this week. Mr Trump had to be reminded of the long-held tradition that departing presidents tend to leave letters to their successor when he returned to office on Monday.