Table 1.

Summary of the workshop content and co-design activities

Workshop No.	Stakeholders	Content and Co-design activities
1 2	12 mothers 5 mothers	Both workshops were held on the same day at a community centre based in London and followed the same format. Stakeholders were guided to share insights and ideas around concerns and improvements or alternatives across possible universal interventions, identified from research stream 3. Stakeholders explored which interventions were acceptable, why, and how they could be improved, through a traffic light system activity. They also shared insights into solutions to any barriers identified.
3 4	5 mothers 2 mothers	Both workshops were held remotely on the same day using video conferencing software and followed the same format. Stakeholders were guided to share insights and ideas on risk factor-specific interventions for mental health, substance use, domestic violence, and poverty, identified from research stream 3. They explored which interventions were acceptable, why, and how they could be improved through group discussion. Stakeholders discussed common principles for interventions and barriers, and issues with resourcing of existing services. They also shared insights into solutions to the barriers identified.
5	6 fathers	This workshop was held at a community centre based in the North-East. Through group discussion, stakeholders identified current support benefits as well as barriers and issues with existing services and interventions as discussed in previous workshops. They shared ideas on how to tailor services/interventions around inclusivity for fathers and how they would experience an intervention.
6	11 young people (aged 13–18 years)	This workshop was held at a community centre based in the North-East. Through group discussion, stakeholders identified current support benefits as well as barriers and issues with existing services and interventions as discussed in previous workshops. They shared ideas on how to tailor services/interventions around inclusivity for children and young people through the development of personas for a service provider and the young people who may use a service. They utilised the personas to map out the experience of a young person going through a service and their interactions with a service provider.