Table 1

Description of sample

Participant number	Stakeholder type	Level of involvement	Further relevant characteristics
Secondary data source: initial 14 interviews
1	Public Health Executive	Indirect, external to programme	Female Involved in commissioning at a senior level within the target area for several years
2	Director of an Academic Health Science Centre	Indirect, external to programme	Female Involved in non-SRH digital health services development
3	Healthcare Commissioner	Indirect, external to programme	Female Senior commissioner within target area
4	Senior Manager within Clinical Services	Indirect, external to programme	Female Involved in provider management in NHS Trust within target area
5	Senior Manager within Clinical Services	Indirect, external to programme	Male Involved in provider management in NHS Trust within target area
6	Senior Manager within Clinical Services	Indirect, external to programme	Male Involved in technical infrastructure of clinical services
7	Senior Nurse in SRH Services	Indirect, external to programme	Female
8	Senior Consultant in SRH Services	Direct, internal to programme	Male Involved in the development of various digital and online SRH services including this programme
9	GP within target area	Indirect, external to programme	Female SRH lead
10	Client Support Worker	Indirect, external to programme	Male
11	Service-users of local SRH services and potential service-user of SH:24	Indirect, external to programme	Male MSM
12	Service-users of local SRH services and potential service-user of SH:24	Indirect, external to programme	Female BAME Local resident
13	Service-users of local SRH services and potential service-user of SH:24	Indirect, external to programme	Female BAME Local resident
14	Service-users of local SRH services and potential service-user of SH:24	Indirect, external to programme	Female BAME Local resident
Primary data: supplementary sample
15	Developer of online SRH services for target population	Indirect, external to programme	Female Previously worked for a national provider of online health services
16	Public Health Registrar working within target area	Indirect, external to programme	Female Contraceptive service-user Previous involvement in pharmacy provision of contraception
17	Senior Manager of SRH services for target population	Some limited direct involvement through seat on board of external stakeholders	Female Member of board of external stakeholders of online service
18	Senior outreach worker in target population	Indirect, external to programme	Female
19	Senior Contraceptive Nurse	Indirect, external to programme	Female Previous involvement in online SRH services Reproductive health researcher
20	Reproductive Health Consultant	Indirect, external to programme	Male Consultant for private, online contraceptive service
21	Public Health Registrar and researcher of online health	Direct involvement with programme through research activities	Female Safeguarding expert

BAME, black, Asian and minority ethnic; GP, general practitioner; NHS, National Health Service; SRH, sexual and reproductive health.