Purpose The paper reports the preliminary evaluation findings of an integration programme in the children’s health care sector in the North West of England. The programme was led by the local Clinical Commissioning Group (CCG) utilising a semi-autonomous working group model. It comprised horizontal and vertical integration. The evaluation reflects the emerging policy context of CCG leadership in the field of health care planning and commissioning. Design/methodology/approach The evaluation used a mixed method observational study design to obtain the views and opinions of stakeholders and measured their change over time. A series of initial semi-structured interviews was conducted with purposively selected key professionals in strategic positions to assist in designing a survey instrument. An online survey was launched at programme inception and repeated at 5 months. Respondents were members of 5 implementation working groups. Survey responses were subjected to a descriptive analysis and tests of correlation. Findings The data showed high levels of commitment and perceptions of shared vision and goals amongst respondents which were relatively stable over time. Responses also indicated that the programme was perceived to have a considerable impact on collaborative work but that this initial effect decreased over time. There were no significant attitudinal differences across sectors or professional groups. Originality/value The study demonstrates the strengths and weaknesses of the multi-agency working group model to implement change. Whilst confirming initial positive effects of integration programmes on collaborative work, over time this appears to wear off to be replaced by increased levels of skepticism amongst participants. Our findings have implications for service commissioners and service planners engaging in vertical or horizontal integration of children's services.