On the morning of polling day of the EU referendum, the #UseAPen meme began to trend on Twitter – so much so that by mid-afternoon the Washington Post had reported on it and canvassers were encountering it on doorsteps.

For those not familiar with #UseAPen, this was a widespread concern which spread on social media about the idea that ballots cast in pencil would be rubbed out by electoral officials. Many went so far as to attend polling stations with spare pens for fellow voters.