His commitment to his studies meant he missed out on being a part of the first Lions tour since prior to the outbreak of the First World War.
His decision may have prevented him from being awarded the highest honour for a rugby player from Britain or Ireland but his career path after rugby clearly shows that it had a far from negative impact on his academic and business achievements.
The Llanelli County School product had already achieved a 1st Class degree in chemistry at Aberystwyth before taking up the challenge of a Phd at the world-famous red-brick university.
While at Cambridge, he found time to win three Blues, losing to Oxford in 1923, '24 and '25, and also turned out for London Welsh and Llanelli. It was from the latter that he won his four caps in 1925, captaining Wales against Ireland at Ravenhill in his final Test.
A family passion for science and public service
After rugby, Idris became a distinguished scientist who was made a CBE in 1954.
In 1933 he became the research manager of Powell Dyffryn Limited and was appointed director-general of research at the National Coal Board in 1946. In 1962 he became director-general of research and development (Coal Processing and Combustion) at the National Coal Board.
He was also chairman of the Appointments Board of the University College of Wales for more than a decade and vice-president of the University from 1968.
His younger brother, Elwyn, was a high court judge who took an instrumental part in the trials of Nazi war criminals at Nuremberg. A Labour MP for more than 30 years, he became Lord Elwyn Jones, or Baron Elwyn Jones of Llanelli, and was Attorney General from 1966-70 and Lord Chancellor from 1974-79.