Analysis of the Commission's role in policy implementation has focused largely on the administrative rather than political level. Yet little attention has been paid to the importance of high-level Commission actors, such as Commissioners and Director-Generals at this stage. This article analyses the role of a working group (WG) of Commissioners in monitoring and co-ordinating the implementation of trans-European networks (TENs) in transport. It argues that formally institutionalized structures for intra-College co-operation provide important arenas for creativity, entrepreneurship and consensus-building. Ultimately, the consistent and sustained political involvement of Commissioners improves the Commission's administrative co-ordination and may, ultimately, help secure better policy implementation.