NPL has been responsible since 1950 for the radio time signal used to set the UK's clocks, known by its call-sign MSF. The signal was originally broadcast from Rugby, but since April 2007 it has been transmitted by VT Communications (now Babcock) from Anthorn radio station in Cumbria, under a contract with NPL.

Maintaining accurate time is essential for keeping the modern world working. Global navigation systems, the internet, e-mail, television, the power industry, transport and financial systems are just some of the industry sectors that depend on accurate time for their operations.

The transmitted time signal is correct to within one millisecond (one thousandth of a second) of the world time standard Coordinated Universal Time (UTC) and supports a wide range of services. These include emergency 999 communications, train companies, cash machines and mobile phone billing systems.

The signal's transmission is linked to NPL's atomic clocks at Teddington in south-west London. NPL is home to the nation's time scale and is one of only seven laboratories worldwide using the latest caesium fountain standards to contribute to UTC.

Find out more about NPL's research in Time & Frequency