News and Comment

Happy Leap Second Day!

Tuesday 30 June 2015


Blink.. and you just might miss it.

Scientists are adding an extra second to our clocks on Tuesday, June 30. The one extra second is called a ‘leap second,’ and put simply, every few years it ensures that the Earth’s rotation, which is gradually slowing, catches up with atomic clocks, keeping official time neatly in sync with night and day.

Leap seconds have been added to the world’s computers around once a year since 1972 – this is the 27th – but this occasion could also be the last. The world’s time keepers are divided over the issue, with some arguing that the periodic insertion of leap seconds can cause problems to systems such as computers and communications networks.

In May 2014 the then Science and Universities Minister David Willetts launched a public dialogue on leap seconds to help inform the future position of the UK Government on this ‘timely’ issue. The National Measurement Office (now the National Measurement and Regulation Office), in conjunction with Sciencewise, commissioned OPM Group to conduct this public dialogue throughout the UK.

A final decision on whether to keep time linked to the sun and the earth’s rotation, or to stop adding the leap seconds which maintain the link is due to be reached in November at a meeting of the International Telecommunications Union, the relevant UN body. Until then, OPM’s Leap Seconds UK Public Dialogue Final Report and blog present the public’s view of the full implications of ceasing the relationship between the sun and the time on our clocks.


If you have any further questions about the dialogue, please contact OPM’s Tracey Bedford or email more information on the methodology and outcome, please see the Leap Seconds UK Public Dialogue case study.