Dead currency. Replaced with the one pound coin.
I have dim
memories of one pound notes from my very early
childhood. They were phased out in
1983, as due to inflation their value was negligible, and coins are much more
robust and less fiddly. The introduction of £1 coins meant that
vending machines didn't have to have those awfully unreliable note-readers which I met while in
America.
The final issue notes were small (about the size of modern-day £5 notes) and blue/green, with
Queen Elizabeth II on one side (
natch), and
Sir Isaac Newton on the other.
All the maths
textbooks I used at school featured £1 notes, which is probably why I remember them, seeing as I was two when they were phased out. A pleasing
anachronism for a five year old. I seem to remember that the
Bank of Scotland or
Clydesdale Bank still issues £1 notes. Please /msg me if you can confirm/disprove this.