Background Theoretically, there may be benefit in augmenting school-based sexual health education with sexual health services, but the outcomes are poorly understood. Healthy Respect 2 (HR2) combined sex education with youth-friendly sexual health services, media campaigns and branding, and encouraged joint working between health services, local government and the voluntary sector.

This study examined whether HR2: (1) improved young people's sexual health knowledge, attitudes, behaviour and use of sexual health services and (2) reduced socioeconomic inequalities in sexual health.

Methods A quasi-experiment in which the intervention and comparison areas were matched for teenage pregnancy and terminations, and schools were matched by social deprivation. 5283 pupils aged 15–16 years (2269 intervention, 3014 comparison) were recruited to cross-sectional surveys in 2007, 2008 and 2009.

Results The intervention improved males’ and, to a lesser extent, females’ sexual health knowledge. Males’ intention to use condoms, and reported use of condoms, was unaffected, compared with a reduction in both among males in the comparison arm. Although females exposed to the intervention became less accepting of condoms, there was no change in their intention to use condoms and reported condom use. Pupils became more tolerant of sexual coercion in both the intervention and comparison arms. Attitudes towards same-sex relationships remained largely unaffected. More pupils in the HR2 area used sexual health services, including those from lower socioeconomic backgrounds. This aside, sexual health inequalities remained.

Conclusions Combining school-based sex education and sexual health clinics has a limited impact. Interventions that address the upstream causes of poor sexual health, such as a detrimental sociocultural environment, represent promising alternatives. These should prioritise the most vulnerable young people.