Time in the city

We provide time services to support industry, enable innovation and deliver confidence. 

Why NPL?

In 1955, timekeeping in the UK reached a turning point when Louis Essen, a physicist at the National Physical Laboratory (NPL) developed the world’s first working caesium atomic clock. 

And today..

As the home of UK time, we maintain the national time scale and disseminate time across the UK. We contribute to global timekeeping and the global reference time system, Coordinated Universal Time (UTC). By applying very fine adjustments to atomic clock frequencies, UTC(NPL) is kept within a few nanoseconds of UTC. 

Our expertise in maintaining time standards helps keep our daily lives running on time with accurate timekeeping that is crucial to our quality of life. The accuracy of timekeeping impacts on everything satellite navigation systems, underpins the functioning of the internet and facilitates timestamping for transactions in financial trading. 

Our ability to measure time to this accuracy helps drive economic growth for the UK with trusted timestamping for the finance sector down to the millisecond. We operate two commercial time services, NPLTime Certified^® and NPLTime Access^® 

Hear from Nicolas Bonnet, Director at ICE

Time travel on the Thames

In September 2023, to showcase the story of time we presented the Royal Museums Greenwich with a state of the art strontium ion clock, celebrating the relationship between two organisations who have had, and continue to have, a substantial impact on how the world tells the time.  

A flotilla of boats, led by the Jubilant, rowed from Isleworth to Royal Museums Greenwich, carrying the gifted atomic clock. This momentous occasion marked 21 years since the Jubilant first carried an NPL atomic (caesium) clock down the River Thames.  

The strontium ion clock was the most accurate atomic clock in the world in 2004 and consists of a single ion of strontium trapped and cooled within the vacuum chamber. Our latest optical clocks are more than 100 times more accurate, and one has recently started contributing to International Atomic Time. 

We continue to showcase the importance of accurate and resilient timekeeping in our daily lives. Through our longstanding relationship with Royal Museums Greenwich, the clock now provides the public the chance to view a prestigious piece of scientific equipment and learn about its vital role in the UK’s timekeeping history. 

Time travels along the River Thames

Tackling societal challenges with science

Our scientists apply their knowledge and expertise to many of the challenges facing society today. Our mission is to provide the measurement capability to underpin the UK’s prosperity and quality of life and we took the opportunity to share our expertise in partnership with the Royal Institution of Great Britain with a series of inspiring talks covering key topics in our modern world: precision timekeeping, understanding climate change and the potential of quantum technologies.

Why is precision timekeeping so important?

Consistently available and accurate timing is a commodity we often take for granted, but its integration with technology impacts us all. There is worldwide dependency on timing accuracy, it is key for phase synchronisation of the power grid, synchronisation of telecoms and broadcast networks, traceable timestamping for regulatory compliance in the financial sector and timestamps for safety critical data.

Unleashing the power of satellites

Measuring changes to the Earth’s atmosphere is a complex challenge. Understanding the impact that any climate mitigation actions have on our atmosphere requires information from many different sources and may use measurements which span decade-long timescales. TRUTHS, invented by Professor Nigel Fox at NPL, is a climate focused satellite mission, led by the UK Space Agency (UKSA) in partnership with several European states. Delivered by the European Space Agency (ESA), it will facilitate improved understanding of changes in the Earth’s climate and the response to the worlds net zero agenda.

“Professor Nigel Fox and I told the story of the TRUTHS mission and how it fits into NPL’s work in satellite Earth observation. It was great to see such a captivated audience and receive challenging and thought-provoking questions around the climate and our role in measuring it.” - Emma Woolliams, Principal Scientist in Earth observation and presenter of ‘Unleashing the power of satellites’.

Time is an invisible utility, and many people don’t realise just how crucial it is until we lose it. I hope that my colleagues and I were able to inspire the audience to think more deeply about time on this level and that they took away some new knowledge to share with others.

Dr Leon Lobo - Head of the National Timing Centre at NPL and presenter of “Why is precision timekeeping so important?"

The future of measurement with quantum sensors

We create the new facilities and deliver world-class research based on quantum phenomena. This enables the translation of quantum technologies and materials into practical applications and underpins new standards, accelerating the commercialisation of new products based on quantum systems. Dr JT Janssen our Chief Scientist explains the work NPL does, as quantum phenomena are set to change the world around us.