Objective The evolution of the planning governance system for ecological infrastructure is an essential guarantee for giving full play to the role of ecological infrastructure in systematic life support and green transformation. According to relevant academic researches, the planning governance for ecological infrastructure in China still needs to be improved against such problems as the simplicity inclination of objective orientation, the insufficient ubiquity of collaborative governance organization, and the inadequacy of quantitative evaluation methods and standards for ecological value. This research aims to clarify the evolution process and the latest features of the planning governance for ecological infrastructure in the UK, and to draw inspiration therefrom to relevant practice in China.

Methods This research first identifies the substance of the term "ecological infrastructure" in the UK policies from the perspective of space, function and the supporting role of ecological infrastructure in urban construction, and elaborates the inherent requirements thereof including systematic plan formulation, innovative construction mode, comprehensive ecological benefits and corresponding high-level planning governance. After that, the research combs the key contents related to the governance of ecological infrastructure in relevant policies, regulations, plans and researches issued or conducted during the period from 2003 and 2021 in the UK, and has the evolution process of the planning governance for ecological infrastructure divided into three stages, with the progress of each stage being summarized. On this basis, the research refines the latest features and advantages of the planning governance for ecological infrastructure in the UK from the perspective of governance orientation, governance organization and governance mechanism. Finally, in combination with the key issues under the objective of high-quality development of urban construction in China, the research clarifies relevant experience and inspirations that can be drawn from the UK by demonstrating relevant experimental practice in some domestic cities.

Results The evolution of the planning governance for ecological infrastructure in the UK exhibits variations between the three stages. In the first stage, under the overall objective of urban development strategies such as the sustainable communities agenda, the growth point agenda and the eco-towns worksheet, the construction and governance of ecological infrastructure were carried out as one of the main principles in limited experimental places, which were invested by the government especially for the aforesaid strategies. In the second stage, in the context of planning system reform characterized by localism enhancement, the practice of planning-making and governance of ecological infrastructure was carried out in most cities and regions in the UK, which improved the plan formulation system and plan management framework for guiding construction of ecological infrastructure. In the third stage, under the development objective of green transformation, the accounting and transaction mechanism for ecological value was developed dramatically at the national level and in some large cities including London, which effectively supported the planning, construction and investment decision-making of ecological infrastructure. During the period from 2003 to 2021, the development tendency of planning governance for ecological infrastructure in the UK presented features and advantages especially in three main aspects. 1) The governance orientation transformed from improving ecosystem service to supporting green development. The latest governance orientation turns out to be urban construction model adapted to key issues including green lifestyle promotion, air pollution alleviation, intensive land use and industrial upgrading. 2) The governance organization evolved from the fragmentation of ownership and management to the collaboration of various subjects at different levels. The latest governance organization can be applied at different scales and in all regions to maximize the functions of ecological infrastructure. 3) The focus of governance mechanism shifted from public interest overview to comprehensive asset value identification and economic benefit accounting. The latest governance mechanism well justifies social investment and public budget, and thus guarantees sustainable construction and conservation of ecological infrastructure.

Conclusion Based on the aforesaid efforts, the research draws the following three conclusions. 1) Under the prevailing condition of tight constraints on resources and environment in Chinese cities at present, it is necessary to build policy tools for ecological infrastructure under the framework of the overall urban or regional development objectives. The practice of planning governance under the more comprehensive objective orientation of green transformation can give full play the role of ecological infrastructure in cultivating green lifestyle, increasing the proportion of green transportation and placing innovation economy in high-density areas, thus releasing the ecological, cultural, social and economic values of ecological infrastructure. 2) Given that diverse ecological resources and spaces are to be integrated into a composite network in line with the connotations of ecological infrastructure, the governance organization characterized by level cooperation, regional coordination and department collaboration should be established. A more coordinated approach to governance organization that can maximize the function of green infrastructure by breaking through restrictive factors such as sector management and administrative division while taking into account both the overall objective and diverse demands of different subordinate places should be developed. 3) A value accounting and transaction mechanism covering all kinds of component elements of ecological infrastructure in the whole administrative region should be established, which is supposed to be able to improve ecological benefits and value for cities, while exploring new sustainable development opportunities and models for rural and environmentally sensitive areas. By providing a chance for positive interaction between the promoters and the beneficiaries of ecological value, the aforesaid mechanism can ensure the sustainable improvement of ecological value and rational distribution of ecological products.