This paper outlines the approach taken and findings from a national social work practice development event, the MCA Call to Action. In March 2016, the adult social work Principal Social Worker Network ran the first Call to Action in support of the Ministry of Justice Mental Capacity Action Day. The MCA Call to Action was conceived and designed as a critical and creative way to conduct practice-led research into the integration into social work values of the statutory principles within the MCA 2005. The approach made use of the open social media platform, twitter. Thematic analysis was undertaken of the content generated during the Call to Action. Secondary social network analysis was undertaken to map the relationships and exchanges which took place during the MCA Call to Action. The findings were that 269 unique users participated in the MCA Call to Action, two thirds of which self-identified as being social workers during the MCA Call to action. There were 244 media tweets posted during the Call to Action showing an image of an unwise decision, 80% of these were posted by social workers. The role of Principal Social Workers and the implications for social work practice leadership are discussed.