In a jury trial for attempted rape, when there is substantial evidence of victim’s equivocal conduct that would have led defendant to reasonably and in good faith to believe consent existed when it did not, it is error not to instruct on mistaken belief of consent. Appellant and the victim met each other at a bar. The two struck up a conversation and appellant bought her a beer. Over the evening, they remained with each other, becoming somewhat amorous and continuing to drink. Appellant then accompanied her home. At this point, appellants and the victims accounts of the following events differed, with appellant testifying that the two engaged in mutual foreplay while the victim testified that when she came out of the bathroom, appellant forced himself on her although she objected. Evidence was also presented that at the time of the claimed assault, the victims blood alcohol level, based on the amount of alcohol she reportedly consumed, would have been approximately .20%. The court failed to instruct on good faith but mistaken belief in consent. The jury was unable to reach a verdict on some of the charged sex offenses, acquitted appellant of attempted sexual penetration by force, but convicted him of attempted rape by force. The appellate court rejected the Attorney Generals contention that because victim and appellant gave contradictory versions of the incident, and because appellant stopped his advances when she rejected him, appellant was not entitled to a mistaken consent instruction. “A requested instruction regarding mistake of fact [is] required when some evidence deserving of . . . consideration exist[s] to support that contention.” (People v. Mayberry (1975) 15 Cal.3d 143, 157.) Here, the evidence was such that the jury should have been instructed on appellants good faith but mistaken belief in consent. The error was prejudicial because if the jury found that appellant had a reasonable belief that the victim consented, he lacked the specific intent for rape.