Britain’s long-standing role as the guardian of the world’s time standard is facing change after new recommendations from the International Telecommunication Union (ITU) proposed a more precise method for defining and distributing global time.
Under the recommendations, responsibility for coordinating international timekeeping could shift from the traditional Greenwich-based system to the International Bureau of Weights and Measures (BIPM) in Paris. The BIPM already plays a central role in maintaining the international system of units and coordinating atomic time standards.
At an ITU meeting in Geneva last week, US Navy scientist Ronald Beard, who chaired the working group that produced the proposals, told FRANCE 24 that Greenwich Mean Time (GMT) has been regarded by scientists as problematic since the 1920s. He noted that Coordinated Universal Time (UTC), introduced in 1972 and based on highly accurate atomic clocks, effectively replaced GMT for precision needs.
Historically, time was determined by the Earth’s rotation: the position of the sun as it crossed the north-south meridian line passing through Greenwich in London set the standard. However, that astronomical method is imperfect because the Earth’s rotation is not constant. Small variations—on the order of seconds over long periods—mean the rotation slows and speeds unpredictably. To compensate, UTC currently employs occasional leap seconds to keep civil time aligned with Earth’s rotation. That ad hoc insertion of leap seconds is increasingly seen as inadequate for modern communications, navigation, and scientific systems that demand continuous, predictable time scales.
Proponents of the ITU recommendations argue that using a time standard rooted in atomic clocks and coordinated by an international metrology body would provide greater long-term stability and better support advanced technologies—ranging from satellite navigation to high-frequency trading—that cannot tolerate irregular adjustments. Critics warn that any shift must preserve continuity for legal, historical, and everyday uses of time, and that careful planning is required to avoid disruptions.
No final decision will be taken immediately: the ITU plans to vote on the proposed changes in January next year. If approved, the change would mark a major shift in how global time is managed and could diminish Britain’s historic symbolic role tied to Greenwich, while formalizing a system centered on atomic timekeeping and international coordination through the BIPM.