Dealing with Unprecedented Scale and Complexity: Lessons from Archiving HS2 Digital Archaeological Data

As the UK’s largest linear infrastructure project, High Speed 2 (HS2) necessitated the nation's most extensive archaeological programme. The project's monumental scale and complexity posed risks to data consistency, preservation, and reuse. The Archaeology Data Service (ADS) was mandated to manage this challenge, overseeing over 34 terabytes of heterogeneous data. This volume exposed the limitations of existing frameworks while providing a unique opportunity for innovation in archiving infrastructure and rationale. This paper reflects on how the ADS was transformed by HS2, evolving its technical capacity alongside its understanding of the organisational and ethical dimensions of large-scale curation. These challenges served as a proving ground for testing future-proofed data management approaches. The resulting tools, workflows, and perspectives have expanded the ADS’s capacity to ensure data integrity in perpetuity, ultimately providing a long-term infrastructural benefit to the wider archaeological sector.