This study sought to examine the subjective experiences and interpretations of factors facilitating or blocking the implementation and diffusion of process-based healthcare innovations. It did this by exploring innovators' own accounts of these processes. Overall, our results elicited themes commonly found in the literature of innovation diffusion, echoing previous studies [33, 34]. Significantly, the notion of evidence consistently emerged as the key leitmotif in narratives of the innovation journey. The development of social networks, both inter-personal, expressed through champions and advocates, and inter-organisational, was an additional critical theme, while both the immediate organisational context and the wider socio-political and economic environment were recurrently articulated as major influencing factors.
Evidence was constructed as a powerful parameter that provided innovators with a sound base for their own assessment in turn allowing the initiation and diffusion of innovation. Evidential knowledge constituted a transparent, unbiased and credible source, from which innovators could extract their arguments and could structure their persuasive efforts in terms of innovation utility and effectiveness. As May et al.  suggested "evidential knowledge serves a stabilising purpose for ideational claims" (p. 703). The desire for "hard" or numerical evidence dominated. This was evident, not simply around those innovations which were more clinically-oriented but was also considered vital for innovations less centrally-related to healthcare provision or led by non-medical staff. Here too numerical or financial descriptors were aspired to; they provided ideal metrics for indicating the impact of the innovation. Importantly, a polarisation was observed with innovators often contrasting numerical evidence with experiential testimonies or anecdotal evidence, while the potential for a rigorous qualitative assessment of the value of the initiative was absent from peoples' accounts. The strong reliance on quantification and the accompanying disregard of experiential knowledge is reflective of the pursuit of objectivity. Quantitative data and the highly structured rules for producing this have been rendered as a powerful tool for conferring trustworthiness to knowledge claims, appearing exempt from subjective judgments and local singularities .
Although evidence was depicted as a powerful tool from the innovators' point of view, they did not claim that the evidence they had assembled were necessarily the most accurate or reliable metrics of innovation effectiveness or consider that it would be uncontested and readily acceptable among a broader range of stakeholders. Indeed, the innovators were often aware of the weaknesses or deficiencies of their approach and expressed a desire for more or stronger evidence [Vasileiou, Barnett, Young, unpublished data]. The evidence they were able to collect and produce seemed enough to convince immediate stakeholders but how compelling it was considered to be for a broader audience was much more questionable.
Arguably, the ubiquitous preoccupation with evidence reflects the strong profile of the "evidence-based practice" movement within healthcare sector since the early 1990s . Though deriving from the medical community, our findings suggest that representations of evidence-based practice and of its value have been assimilated by other professional fields within healthcare. The sort of evidence perceived as adequate and thus persuasive varied considerably across the professional memberships of innovators, with medical staff espousing almost exclusively scientifically derived evidence, while other professionals contented themselves with statistics and financial figures. However, conviction concerning the necessity, transparency and objectivity of empirical data for the audit of innovations was common to all. Ultimately, evidence was constructed as the tool which would legitimate an unproblematic and direct diffusion of innovations within a sector that traditionally relied on scientific knowledge. Other sources of knowledge, such as experience, would fail to do so especially under the burden of uncertainty and risks that any organisational change embodies. Consequently, evidence constituted a stable and substantial reference point from which arguments of innovation utility could be justified and practices of persuasion could be initiated.
Several types of inter-organisational links (e.g. structural, administrative, institutional, or resource links) have been conceptualised as antecedents of organisational innovativeness . In this study partnerships were not only seen as a prerequisite of innovation, but also as a result of innovation; inter-organisational links were part of the essence of the innovation itself. This was highly valued and constructed as an important "legacy" for the local community.
Our findings suggest that inter-organisational links served two important and complementary purposes: material and symbolic. Materially-based partnerships provided the innovative organisation with the necessary resources, required for the implementation and diffusion of initiatives. Symbolically, inter-organisational exchanges allowed organisations to gain local consensus and therefore to bolster the new service with legitimacy. Particularly when innovations were perceived to be radical, proactive engagement with various stakeholders was common. Consequently, inter-organisational collaboration was not only seen as vital to securing resources but also as an important social exchange that assisted with powering innovation through gaining a broader consensual base.
Reinvention  on the part of prospective adopters was a common theme in that innovators expected others to adapt and modify the innovation in the new context thus increasing the likelihood of sustainable diffusion. For those leading the development of new services in healthcare settings, having an identity of "successful innovator" was both feasible and desirable. It was thus vital to the maintenance of that identity that potential adopters in other healthcare organisations should understand that the initiatives were highly context-specific (see also ) and thus their active adoption in new contexts all but constituted another innovation.
Finally, our findings indicate the importance of a supportive environment for the establishment and diffusion of service innovation along with the technological enablers, as this is proposed in the theory of disruptive innovation [22, 23]. The example of the multilateral innovation around sustainability is informative: most of the single initiatives within this innovation-green IT developments, sustainable transportation scheme-resonated with the broader spirit of environmentalism and energy-saving policies and were implemented successfully. However there was a particular case-the construction of a sustainable food procurement unit-which, even though it could bring significant cost-savings and was consonant with the sustainability agenda adopted by the Trust, was nevertheless severely impeded due to the absence of a regulatory body within healthcare that would align, support and coordinate the relevant activities.
Limitations and strengths of the present study
One limitation of this research is its cross-sectional design which precludes an examination of the underlying processes of innovation initiation, implementation and diffusion, as a longitudinal study would have done.
However, this study provided the unique insights and experiences of healthcare innovators who had conceived and led process-oriented innovations. Innovators can contribute significantly in the diffusion of new initiatives, as they often appear willing to lead constructive efforts of dissemination, operating as powerful champions. They are able to advise and indicate the most promising ways of adoption and implementation, since they carry valuable experience of their own efforts to implement the initiative in their organisations. However attention should be paid as to what stages of diffusion innovators are more likely to contribute positively, since high levels of champions' identification with their role or organisation may actually impede further innovation diffusion . On-going support of healthcare innovators, especially in their attempts to promulgate and publicise the novelty, is crucial for the dissemination of new initiatives.