Born in Sheerness in Kent,[1] Beynon attended Borden Grammar School, then the University of Bristol, from which he received a degree in mathematics.
After completing National Service with the Royal Artillery, he returned to Bristol where he qualified as a teacher.
[2] As joint leader of the union, Beynon championed the introduction of a "conscience clause", meaning that even if the union voted to take industrial action, individual members could decide not to take part.
He represented the union on the Burnham Committee for many years, and was its chair from 1985 until it was abolished in 1987.
[1] Beynon retired in 1987, thereafter serving on a number of committees, including the executive of the Welwyn Garden City Society.