Underdog was created in 2010 for the insurance provider National Accident Helpline, as a claymation figure (often seen with bandages on his arms, legs and ears).

The initial concept of Underdog was created by The Gate London advertising agency, where Dave Trott is chairman.

[2] The design of Underdog bears a close resemblance to that of the principal characters from Aardman's earlier TV series Rex the Runt created by animator Richard Starzak.

Underdog first appeared in ads standing in the shadow of a tall figure voiced by Brian Blessed, using his catchphrase "I've had an accident!"

The most recent run of ads (beginning in September 2013) featured computer-generated imagery created by Aardman Animations.