What are the requirements for a jury to consider the elements of robbery and theft in a jury trial?

In any criminal matter, the jury must be instructed on all crimes necessarily included within the offense charged if there is substantial evidence from which a reasonable jury could conclude the defendant is guilty only of the lesser offense. (People v. Birks (1998) 19 Cal.4th 108, 118.) This obligation exists even absent a request and even over the parties' objections. (Ibid.)

"Robbery is the felonious taking of personal property in the possession of another, from his person or immediate presence, and against his will, accomplished by means of force or fear." (Pen. Code, 211.) Theft is a lesser included offense of robbery, lacking only the element of force or fear. (People v. Melton (1988) 44 Cal.3d 713, 746.)