What is Mater's formal title after the royal ceremony in Pixar's Cars 2?

Mater's formal title after the royal ceremony in Pixar's Cars 2 is Sir Tow Mater.

Mater receives the honor from the Queen of the United Kingdom after helping stop the conspiracy surrounding the World Grand Prix. The title is a comic play on his name: “tow” describes his job as a tow truck, while “Sir” is a British honorific conferred through knighthood.

Mater travels abroad with Lightning McQueen and becomes involved in the spy adventure after being mistaken for an American agent. Although he appears clumsy and unsophisticated to the other characters, his observations and improvisation ultimately expose the villains' plan. The ceremony provides a formal ending to his unexpectedly heroic role.

The title should not be confused with Mater's ordinary name, Tow Mater. It is also separate from his Radiator Springs occupation and from the identities of the professional spies Finn McMissile and Holley Shiftwell. The film uses the ceremony as a joke and as recognition of Mater's contribution.