ABSTRACT
Empirical research has demonstrated the pivotal role of leadership in implementing evidence-based interventions. However, little is known about the interpersonal factors that support or hinder collaboration between senior leaders, particularly in complex, multi-agency settings. This study explored interpersonal factors influencing collaborative leadership during the implementation of Multisystemic Therapy and Functional Family Therapy within the Pan-London Positive Families Partnership, a cross-borough initiative for children on the edge-of-care. Twelve senior leaders participated in semi-structured interviews. Reflexive thematic analysis identified two overarching themes: ‘the importance of a relational approach’ and an ‘adaptive and reflective way of being’, encompassing six subthemes. Findings highlighted the centrality of relational leadership practices, underpinned by psychological safety and informed by attachment principles, containment, mentalisation and adaptability. Leaders enacted strategies that mirrored interventions’ therapeutic ethos, fostering trust, supporting collaboration and buffering teams from systemic pressures. This alignment between leadership culture and clinical practice was critical for coherence across organisational layers. This study adds to evidence that relational leadership, underpinned by psychological safety, supports implementation and sustainment of evidence-based interventions in complex systems. By illustrating interpersonal processes, it reinforces the need for models that integrate attachment and relational dynamics to enhance leadership capacity and outcomes for young people and families.