1 B Eberlein and E Grande, “Beyond delegation: transnational regulatory regimes and the EU regulatory state” (2005) 12 Journal of European Public Policy 89.

2 D Puchala, “Domestic politics and regional harmonization in the European Communities” (1975) 27 World Politics 496.

3 Consolidated Version of the Treaty on the European Union [2012] OJ 1 325/5/01.

4 RD Kelemen, “Suing for Europe. Adversarial Legalism and European Governance” (2006) 39 Comparative Political Studies 1011.

5 E Mastenbroek and D Martinsen, “Filling the gap in the European administrative space: The role of administrative networks in EU implementation and enforcement” (2017) Journal of European Public Policy 422.

6 M Hobolth and D Martinsen, “Trans-governmental networks in the European Union: improving compliance effectively?” (2013) 20 Journal of European Public Policy 1406.

7 D Levi-Faur, “Regulatory networks and regulatory agencification: towards a single European regulatory space” (2011) 18 Journal of European Public Policy 810.

8 Eberlein and Grande, supra, note 1; A Gouldson et al, “New alternative and complementary environmental policy instruments and the implementation of the Water Framework Directive” (2008) 18 Environmental Policy and Governance 359; M Martens, “Administrative Integration through the Back Door? The Role and Influence of the European Commission in Trans-governmental Networks within the Environmental Policy Field” (2008) 30 Journal of European Integration 635; Levi-Faur, supra, note 7; Hobolth and Martinsen, supra, note 6; M Maggetti and F Gilardi, “Network governance and the domestic adoption of soft rules” (2014) 21 Journal of European Public Policy 1293.

9 Hobolth and Martinsen, supra, note 6; Maggetti and Gilardi, supra, note 8.

10 H Hofmann, “Mapping the European administrative space” (2008) 31 West European Politics 4.

11 RD Kelemen and AD Tarrant, “The Political Foundations of the Eurocracy” (2011) 34 West European Politics 922.

12 R Keohane, “Governance in a partially globalized world” (2001) 95 American Political Science Review 1; Kelemen and Tarrant, supra, note 11; M Blauberger and B Rittberger, “Conceptualizing and theorizing EU regulatory networks” (2015) 9 Regulation & Governance 367.

13 Mastenbrock and Martinsen, supra, note 5.

14 Maggetti and Gilardi, supra, note 8; Smith, M and Drake, S, “Introduction” in Drake, S and Smith, M (eds), New Directions in the Effective Enforcement of EU Law and Policy (Edward Elgar Publishing, 2016)Google Scholar; D Martinsen and M Hobolth, “The effectiveness of trans-governmental networks: managing the practical application of European integration in the case of SOLVIT” in Drake and Smith, ibid.

15 It must be noted that these functions can partly also be fulfilled by other types of “filling” of the European Administrative Space, notably European agencies. Many of these agencies are also fully or partly networked. See Levi-Faur, supra, note 7.

16 Hobolth and Martinsen, supra, note 6.

17 D Bach and A Newman, “Transgovernmental networks and domestic policy convergence: Evidence from insider trading regulation” (2010) 64 International Organization 505.

18 K Raustiala, “The architecture of international cooperation: Transgovernmental networks and the future of international law” (2002) 43 Virginia Journal of International Law 1.

19 B Bommert, “Collaborative innovation in the public sector” (2010) 11 International Public Management Review 15; J Hartley and J Bennington, “Copy and paste, or graft and transplant? Knowledge sharing through inter-organizational networks” (2006) 26 Public Money and Management 101.

20 E Sørensen and J Torfing, “Introduction: Collaborative innovation in the public sector” (2012) 17(1) The Innovation Journal 1; S Clegg et al, “The transformative power of network dynamics: a research agenda” (2016) 37 Organization Studies 277; Torfing, J, Collaborative Innovation in the Public Sector (Georgetown University Press, 2016)Google Scholar.

21 Torfing, supra, note 20.

22 Smith and Drake, supra, note 14.

23 Martinsen and Hobolth, supra, note 14.

24 Hobolth and Martinsen, supra, note 6.

25 ibid.

26 Slaughter, A-M, A New World Order (Princeton University Press, 2004)Google Scholar.

27 Kopsick, D and Bromm, SE, “North American working group on environmental enforcement and compliance cooperation: moving from capacity building to operational activities” in Fauré, M et al (eds), Environmental Enforcement Networks. Concepts, Implementation and Effectiveness (Edward Elgar Publishing 2015)Google Scholar.

28 J Lehane, “Towards a critical analysis of environmental enforcement networks” in Fauré et al, supra, note 27.

29 Torfing, supra, note 20.

30 ibid.

31 ibid, 65–66.

32 ibid, 105.

33 Torfing, supra, note 20.

34 ibid, p 105.

35 Sørensen and Torfing, supra, note 20.

36 Eberlein and Grande, supra, note 1, p 106.

37 A Turrini et al, “Networking literature about determinants of networks effectiveness” (2010) 88(2) Public Administration 542.

38 Versluis, E, Enforcement Matters: Enforcement and Compliance of European Directives in Four Member States (Eburon, 2003)Google Scholar; C Ansell and A Gash, “Collaborative governance in theory and practice” (2007) 18 Journal of Public Administration Research and Theory 543.

39 Versluis, supra, note 38.

40 Ansell and Gash, supra, note 38.

41 ibid.

42 Torfing, supra, note 20, p 223.

43 J Hartley, “Innovation in governance and public services: Past and present” (2005) 25 Public Money and Management 27 at 32.

44 Eberlein and Grande, supra, note 1, p 103.

45 T Börzel and K Heard-Lauréote, “Networks in EU multi-level governance: concepts and contributions” (2009) 29 Journal of Public Policy 135; K van Boetzelaer and S Princen, “The Quest for Co-ordination in European Regulatory Networks” (2012) 50 Journal of Common Market Studies 819; Versluis, E and Polak, J, “International cooperation via networks and agencies: A tale of perceptions, informality and national cultures” in van der Steen, M and Chin-A-Fat, N (eds), Cross-border Cooperation between National Inspectorates (Netherlands School of Public Administration, 2016)Google Scholar.

46 G Pink, “Environmental enforcement network: theory, practice and potential” in Fauré et al, supra, note 27, p 23.

47 Gouldson et al, supra, note 8; B Eberlein and A Newman, “Escaping the international governance dilemma? Incorporated trans-governmental networks in the European Union” (2008) 21 Governance 25; Martinsen and Hobolth, supra, note 14.

48 EP Weber and AM Khademian, “Wicked Problems, Knowledge Challenges, and Collaborative Capacity Builders in Network Settings” (2008) 68 Public Administration Review 334.

49 Pink, supra, note 46; Slaughter, supra, note 26.

50 ibid.

51 ibid.

52 Torfing, supra, note 20, p 106.

53 Maggetti and Gilardi, supra, note 8.

54 ibid.

55 ibid, p 106.

56 Versluis and Polak, supra, note 45, p 30.

57 ibid, p 29–30.

58 ibid, p 28.

59 JG March and JP Olsen, “The logic of appropriateness” (2004) ARENA Working Papers, 9 <www.sv.uio.no/arena/english/research/publications/arena-working-papers/2001-2010/2004/wp04_9.pdf> accessed 16 August 2019.

60 J Polak and E Versluis, “The virtues of interdependence and informality: An analysis of the role of transnational networks in the implementation of EU directives” in Drake and Smith, supra, note 14, p 113.

61 Eberlein and Grande, supra, note 1, p 101.

62 J Peterson, “Decision-making in the European Union: Towards a framework for analysis” (1995) 2 Journal of European Public Policy 69.

63 M Granovetter, “Economic institutions as social constructions: a framework for analysis” (1992) 35 Acta Sociologica 3.

64 Slaughter, supra, note 26; N Boeger and J Corkin, “Institutional Path-Dependencies in Europe’s Networked Modes of Governance” (2017) 55 Journal of Common Market Studies 974.

65 J Schalk et al, “Network Embeddedness and Public Agency Performance: The Strength of Strong Ties in Dutch Higher Education” (2009) 20 Journal of Public Administration Research and Theory 629.

66 Torfing, supra, note 20, p 106.

67 K Blomqvist and J Levy, “Collaboration capabiility – a focal concept in knowledge creation and collaborative innovation in networks” (2006) 2 International Journal of Management Concepts and Philosophy 31.

68 Ansell and Gash, supra, note 38, p 553.

69 KG Provan and RH Lemaire, “Core concepts and key ideas for understanding public sector organizational networks: Using research to inform scholarship and practice” (2012) 72 Public Administration Review 638.

70 KG Provan and P Kenis, “Modes of network governance: structure, management, and effectiveness” (2008) 18 Journal of Public Administration Research and Theory 229.

71 Martens, supra, note 8.

72 E Versluis and E Tarr, “Improving compliance with European Union law via agencies: The case of the European railway agency” (2013) 51 Journal of Common Market Studies 316.

73 Ansell and Gash, supra, note 38.

74 Torfing, supra, note 20, p 106.

75 Macrory, R, Regulation, Enforcement and Governance in Environmental Law (Hart Publishing, 2014)Google Scholar.

76 AISBL means “association sans but lucratif” [associations without a lucrative purpose], a formal designation under Belgian law.

77 European Network of Prosecutors for the Environment, “Home” (nd) <www.environmentalprosecutors.eu/>, accessed 16 August 2019.

78 Hofmann, supra, note 10.

79 ibid.

80 H Suri, “Purposeful sampling in qualitative research synthesis” (2011) 11 Qualitative Research 63.

81 Guba, E and Lincoln, Y, Fourth Generation Evaluation (SAGE, 1989)Google Scholar; Patton, M, Qualitative Evaluation and Research Methods (SAGE, 1990)Google Scholar; Weiss, C, Methods for Assessing Program Effectiveness (Englewood Cliffs, 1972)Google Scholar.

82 Corbin, J and Strauss, A, Basics of Qualitative Research (Sage, 1990)Google Scholar.

83 O Tansey, “Process Tracing and Elite Interviewing: A Case for Non-Probability Samples” (2007) 40 Political Science and Politics 765.

84 Torenvlied, R, Political Decisions and Agency Performances (Kluwer Academic, 2000)CrossRefGoogle Scholar.

85 M Gibbert et al, “What passes as a rigorous case study?” (2008) 29 Strategic Management Journal 1465.

86 M Hall and T Wyatt, “Environmental prosecution report: tackling environmental crime in Europe” (2017) <www.environmentalprosecutors.eu/sites/default/files/document/Cap%20and%20Gap%20report_FINAL_Print.pdf>, accessed 16 August 2019.

87 ENPE, supra, note 77.

88 The e-nose is a new technology through which (dangerous) odeur can be detected. It is already used in Rotterdam Harbour for example, but has not been yet used to present evidence before court (4). See for more information on the application of e-nose: <www.portofrotterdam.com/en/the-port/safe-port/e-noses-for-a-safe-port>.

89 ENPE makes the following remark with respect to the case law exchanged through the database in its newsletter: “It is important to note that the database is of a non-operational character and concerned with legal aspects only. Names of defendants and other identifying information are left out” (3). Other respondents also note they cannot exchange information on operational cases, or personal information, as operational protocol declares this information confidential (13; 12; 8).

90 While it is beyond the scope of this article to explore the specific outcomes of ENPE, information exchange can also be considered an outcome of ENPE’s collaborative process. The database with environmental case law, discussed in section III, is an example of innovative enforcement through ENPE.

91 Versluis and Tarr, supra, note 72.

92 Hobolth and Martinsen, supra, note 6; Maggetti and Gilardi, supra, note 8.

93 Mastenbroek and Martinsen, supra, note 5; M Scholten, “Mind the trend! Enforcement of EU law has been moving to ‘Brussels’” (2017) 24 Journal of European Public Policy 1348.

94 Torfing, supra, note 20.