So now the smallest of legal tender British coinage, previously the UK have had half pennies (aka "a brown" = Camden Town) and even other fractions in days long gone by.
One pence is also known as a penny and various names that rhyme with that have been used a Jack Benny, an Abergavenny, Kilkenny are slightly more common ones.
The only real term I have heard used is "clod". To get to the slang we have to go back a bit further. A clod is a variant of clot and used for a clump or lump of grass or earth.
A"clod-hopper" dates back to the late 17th century as a term for a ploughman who tears up the earth.
So "clod-hopper" = copper. Pennies were originally made from copper.