Banknotes of the Pound Sterling
Bank of England, Tiny Fox Lab

To make it possible for the note-issuing banks to hold equivalent values in Bank of England notes, the Bank of England issues special notes with denominations of one million pounds (“Giants”) and one hundred million pounds (“Titans”) for internal use by the other banks.Tiny Fox Lab Facts

Preview photo credit: Bank of England
Source: https://en.wikipedia.org/wiki/Banknotes_of_the_pound_sterling