Why was a British sixpence coin called a "tanner"?

Question

Tanner was slang for the silver sixpence coin used before 1971 when the currancy was decimalized. I am wondering why it was called a tanner.

Answer 1

This was because the artwork was designed by John Sigismund Tanner.  It was quite common to refer to a coin by the designer's name when there had been other issues using the same subject.

The $20 Gold Double-Eagle coin used in the States during the early 90s featuring Lady Liberty on the obverse (front) and an eagle on the reverse is referred to as the St. Gaudens since it was designed by Augustus Saint-Gaudens.

Some even abbreviate the name more and just refer to them as "Saints".