On 29 March 2012, Melvyn Bragg hosted an interesting historical discussion about how, when and why it grew increasingly important to measure time accurately, beginning with early civilizations monitoring the slow progress of heavenly bodies, through early medieval pre-pendulum clocks that only needed one hand because there was no demand for accuracy until the railways appeared, and concluding with today when atomic clocks are accurate to within a second every 15 million years!
Called "Measurement of Time", it was part of Radio 4's "In our Time" series and featured Kristen Lippincott (former Director of the Royal Observatory, Greenwich), Jim Bennett (Director of the Museum of the History of Science at the University of Oxford) and Jonathan Betts (Senior Curator of Horology at the Royal Observatory).