The proceedings of the meeting of IAU Commission 31 point out that
The distinction between time epoch and time interval is not clear to everyone.In effort to remedy that situation W. Markowitz, H.M. Smith, and L. Essen introduced an explanatory note on time.
These three noteworthy individuals have stellar biographies
related to the subject of time.
L. Essen was the co-developer of the first cesium atomic chronometer at the UK NPL.
W. Markowitz was the Director of Time at the USNO, had worked on the creation of Ephemeris Time, had been chair of IAU Comm. 31 when Essen announced the cesium chronometer, and immediately acted to perform the calibration of astronomical time scales with the cesium atomic time scale.
H.M. Smith worked at the Greenwich Observatory Time Service and spent the 1970s working with the CCIR to get other agencies to adopt the new UTC with its leap seconds.
This explanatory note was incorporated into the resolutions of the General Assembly (see page 16). Here is the French text. Below is an English translation.
During the subsequent five years the characteristics of the radio broadcast time scale were re-discussed at many more meetings. Despite warnings from astronomers, in 1970 the CCIR decided to implement a new compromise. With no foresight for the problems that would ensue, the leap second was instituted in 1972.
During the decade after the CCIR implemented the leap second in the radio broadcasts they renamed the time scale UTC and promoted the use of the time scale for all applications. As a result UTC with leap seconds was adopted as the perfectly commendable solution by the CCDS, CGPM, IAU, ITU, CCITT, and national governments.
Unfortunately the POSIX committee did not understand the implications of the leap second and considered that precise time was not important for computing. They disregarded advice to allow the leap second to be counted as part of the time scale used in computers, yet they still chose to specify that computers should use UTC. These failures to communicate and comprehend now cause trouble at each successive leap second.