The 2,500 museums, heritage collections and heritage sites in the UK house at least 200 million physical and digital objects. Being able to uniquely identify these objects is key to facilitating their use and curation - you cannot provide a researcher with access to an item or include it in an exhibition if you don't know what it is. Unique accession numbers are therefore a key component in all collection and library management systems but these only include the objects within an individual collection. To fully realise the potential benefits of our national collections in terms of the social and cultural life of the UK, the economic impact of the heritage sector, and the contribution to the UK's international prestige and influence, we need identifiers that will bring together all of the objects from all of the collections. Persistent Identifiers (PIDs) that provide a long-lasting actionable reference to a digital object are recognised by UKRI as a key component of future research infrastructure enabling data discovery, access and citation. Facilitating wider adoption and consistency of approach to the assigning of PIDs to collection objects, environments, specimens and other relevant entities, is a key step to the persistent, unambiguous linking of collections in order to create a digital UK National Collection. However, the challenges, utility and wider benefits of PID implementation are less well understood across the heritage sector. While many individual institutions are using PIDs to a greater or lesser extent, to date there has been very little cross-sector or cross-collection collaboration and / or support to facilitate a cohesive approach that will maximise the benefits to all organisations. This foundation project will bring together best practices in the use of PIDs from a collection perspective, building on existing IRO work and expertise developed through existing research projects. By sharing expertise and best practice, we will provide a framework and recommendations on the approach to PIDs for colleagues in local, regional and national institutions across the UK heritage sector. Through a mixture of workshops, desk research and case studies, the project will seek to answer questions such as 'What are the gaps in the existing PID landscape for heritage collections, buildings and environments?' and 'What should a PID infrastructure, strategy and governance framework look like for a unified UK national collection?'. The project will deliver a set of recommendations to guide the selection, implementation and use of PIDs to heritage collections and related entities and concepts, as well as a number of case studies and supporting resources that can be used across the sector as a guide to real-world PID implementation. In driving the use of PIDs for heritage collections, the project will enable greater use of these collections in all contexts, but especially in research. It will allow improved linking across platforms such as Wikidata, making it easier to associate related concepts and metadata with canonical sources of artefact information and the artefacts themselves. It will provide for the curation and selection of this information from diverse sources to be displayed alongside artefacts in physical spaces and online viewers. Importantly, they will also make this increase in use more evident and measurable, through the improved metrics that PIDs support.