£20 miscut value?

Noticed this note today, curious to see if it is worth anymore than face value. Miscut at the botto and darker at the crown hologram  
 

Unless there is more substrate then normal I can't believe there is any value in a missing piece of banknote (anyone could simply cut off a bit of their banknotes).

Thank you for your response,

my first thought when I saw the note was that someone had cut a piece from the bottom. But when I compared it to a normal note I noticed that the diagonal purple lines went to the end of the note, whereas the cut note had a white gap between the end of purple diagonal lines and the edge of the note, making me think it might be miscut.

below a picture of a normal note 

I think the white gap is a transverse tear in the plastic. The notes are printed in a continuous run from top to bottom, with the bottom pattern continuing onto the next note, and then cut down to individuals. The cut note is likely the same size as other notes.

Even were it to be a print error with a tiny bit of print missing, it is too minor to be worth any premium.