This is the report arising from the study on the impact of Plan S commissioned by the cOAlition S group of funders to assess the impact of their policy intervention five years on since its release in Sep 2018. The study has been conducted by scidecode science consulting in the period Oct 2023-Sep 2024. Its title "Galvanising the Open Access Community" hints at the significant effect that Plan S has had in terms of moving the dial on immediate Open Access. The report is divided in two broad sections addressing the quantitative and the qualitative assessment of the impact of Plan S. For the quantitative analysis, a counterfactual impact evaluation (CIE) has been conducted. This has measured the influence of Plan S on Open Access publishing trends for subsets of publications funded by funding agencies in various countries and regions across the world, both within and outside cOAlition S. The second half of the report is devoted to the qualitative analysis of the impact of Plan S. A series of snapshots examine the current status of different Open Access routes and strategies in the academic publishing domain and the influence Plan S has had and keeps having on these developments. These insights arise from a comprehensive stakeholder engagement exercise whereby interviews and conversations have been held with all relevant actors in the scholarly communications landscape. In view of the findings from both the quantitative and qualitative assessment, the report examines the areas where Plan S and cOAlition S have largely succeeded vs fallen short and issues a number of recommendations to consolidate the impact of Plan S and deepen the effect of cross-funder collaboration. The datasets and code underpinning the Counterfactual Impact Evaluation (CIE) of Plan S are available in an independent 'data + code' record in Zenodo, https://doi.org/10.5281/zenodo.12523229. The files stored in the dataset are also described in Annex 1 in the report.