NPL 125th Anniversary: Metrology, Timekeeping, and AI Futures at the National Physical Laboratory

From its 1900 founding to its 125th anniversary, the National Physical Laboratory (NPL) stands at the core of Britain’s measurement standards. The podcast delves into how NPL protects trade through universally agreed units, chronicles the evolution of timekeeping from mechanical to atomic and optical clocks, and surveys NPL’s cutting-edge work in quantum tech and AI governance. The discussion highlights the ongoing push to redefine the second with optical clocks and the regulatory/measurement challenges posed by rapid AI advancement, underscoring NPL’s role in enabling industry, SMEs, and public policy with robust measurement and trust.

Introduction and 125-Year Legacy

The Naked Scientists team tours the National Physical Laboratory (NPL) as it marks 125 years at the vanguard of metrology, the guardian of the UK’s physical standards. NPL’s early mission centered on tying trade to common units, such as the kilogram and the metre, ensuring reliable international commerce. A key milestone was the UK’s maintenance of national realizations of primary units, with the global system evolving through international agreements. The discussion underscores the enduring importance of measurement accuracy for industry and everyday life, including the persistence of non-SI units like pints and stones, and the necessity of correct conversion factors to avoid errors in global trade.

“The kilogrammes which were distributed around the world came back to Paris and were compared with this original kilogramme.” - JT Jansen

Timekeeping Pioneered at NPL

The program shifts to timekeeping, recounting NPL’s pivotal role in creating the world’s first atomic clock in 1955. The shift from Earth-based time definitions to fixed atomic standards culminated in 1967 with the current cesium-based second. The hosts explain how atomic clocks outperform Earth-rotation-based time, enabling a reliable global timescale and precision necessary for advanced technologies, communications, and science. Optical clocks promise even higher precision, potentially redefining the second again in the near future.

“The second was redefined again to be based on an atomic clock” - Rachel Godden

Quantum Technology and Measurement Science

The conversation then explores NPL’s ongoing contributions to quantum science, from laying foundational concepts to developing practical sensors, quantum networks, and industry partnerships. The lab’s work spans gravity mapping, brain-imaging sensors, and secure communications, all underpinned by meticulous measurement standards and traceability.

“Measurement-based infrastructure underpins AI, data trust, and cross-border trade” - Sandeep Bhandari

AI, Regulation, and Trustworthy AI

As AI accelerates, NPL is building a foundation for trustworthy, safe AI lifecycles, focusing on data quality, model reliability, and explainability. The discussion covers how to mitigate risks associated with large language models by pursuing smaller, focused models trained on trusted data and ensuring data provenance. NPL emphasizes the need to balance rapid innovation with robust standards and policy engagement to protect health, safety, and the environment.

“We need to have confidence in what the AI is doing” - Sandeep Bhandari

Future Outlook

The episode closes with a forward-looking note: optical clocks may redefine timekeeping by 2030, demanding attention to gravitational effects and environmental controls at centimeter or even nanosecond scales. The host and guests reflect on how measurement science opens new avenues for discovery, technology, and the UK’s scientific renaissance, while reaffirming NPL’s mission to enable innovation through precise, trusted measurement.

“Timekeeping will advance with optical clocks and present new challenges in relativity and height measurements” - JT Jansen