Every now and again something takes the public attention and it appears everywhere: Minions now or Pokémon a few years ago. In the 1920s it was Bonzo, a cartoon dog drawn by G E Studdy, a commercial artist. The little dog was an ideal marketing choice, appearing as mechanical and soft toys, car mascots, jigsaw puzzles, postcards and many other things. And one pen! Mentmore caught onto the public fondness for Bonzo and doubtless paid Studdy a fee.

The Bonzo pen was not just a gimmick, however. Mentmore were paying another licence fee, to Wahl, and it may be that it related to the red collar, which is in fact a double section. This enabled changing nibs without completely dismantling the pen as the other section held the sac. In this respect the Bonzo was the forerunner of the Esterbrook, Osmiroid and Platignum pens with their interchangeable nibs.

The Bonzo was a popular pen but not all that many have survived today. They fetch a good price on their own, and much more with the very attractive, colourful box (which I sadly don’t have!)

Thanks to Paul S for photographs.