In R v. Clarkson (1971), what was the reason Ryan could not abandon the doctrine of common design?

The doctrine of common design, or joint enterprise, holds that when individuals participate together in a criminal venture, they share accountability for the actions resulting from that venture. In R v. Clarkson (1971), Ryan's inability to abandon this doctrine is attributed largely to his failure to effectively communicate his opposition to the crime in question.

In a joint enterprise scenario, merely being present is not enough to absolve someone from liability. Effective communication of dissent—both to the co-perpetrators and potentially to law enforcement—is crucial. If an individual remains silent or fails to assert their disagreement, it can be assumed they are complicit in the actions being undertaken, as their lack of objection may be interpreted as agreement or acquiescence. This principle reinforces the importance of active participation and clear communication in distinguishing between those who are genuinely opposed to a criminal act and those who might be deemed to endorse it through their lack of response.

In this case, Ryan's inability to articulate that he was not supportive of the actions taken by others meant that he could not distance himself from the collective responsibility assigned to the group engaging in the criminal act.