<jats:title>Abstract</jats:title> <jats:p>Background Technological solutions may improve the logistics of obtaining parental consent in school-based immunisation programmes. In 2018/19 a health care organisation in London, England, piloted an electronic consent intervention in the adolescent girls’ HPV vaccination programme. We conducted a mixed-methods evaluation to examine the usability and acceptability of the intervention and assess its impact on consent form returns and HPV vaccine uptake. Methods The intervention was implemented in 14 secondary schools in seven South London boroughs. Each e-consent school was matched with a school that used standard paper consent. Matching was based on location and the proportion of students: i. with English as a second language, ii. receiving free school meals (socio-economic status proxy). Consent form return rates and HPV vaccine uptake were compared quantitatively between intervention and matched schools. Data from immunisation session observations (n=7), school feedback forms (n=14), individual and group interviews with implementers (n=8), parents and adolescents (n=12) and a focus group discussion with adolescents was analysed thematically to document user’s experiences investigate the implementation of the intervention. Results HPV vaccination uptake did not differ between e-consent and matched paper consent schools, but timely consent form return was significantly lower in the e-consent schools (73.3% (n=11) vs 91.6% (n=11), p=0.008). The transition to using the system was not straightforward, whilst schools and staff understood the potential benefits, they found it difficult to adapt to new ways of working which removed some level of control from schools. Part of the reason for lower consent form return in e-consent schools was that some parents found the intervention difficult to access and use. Adolescents highlighted the potential for e-consent interventions to by-pass their information needs. Conclusions The e-consent intervention did not improve consent form return or vaccine uptake due to challenges encountered in transitioning to a new way of working. New technologies require embedding before they become incorporated in everyday practice. The intervention is undergoing further iterative development to improve its usability, ensure schools are appropriately involved and adolescents receive tailored immunisation information. A re-evaluation once stakeholders are accustomed to e-consent may be required to understand its impact.</jats:p>