[1] Clemens submitted works to the British Institution's student competition, and his talent was recognized with a two-year scholarship in sculpture paying £50 a year and inclusion in the associated exhibition at the Tate Museum.
[2] After his studies at the Royal College of Art Clemens was appointed assistant master under Professor Édouard Lantéri.
A reviewer for the British Medical Journal thought Clemens's plaster casts of the head of An Orderly, The Pick-a-back and the Camel-Cacolet amply repaid the visitor's attention.
In 1922, Clemens was commissioned by the British Military Nurses Memorial Committee to create a statue for St Paul's Cathedral titled Bombed.
While Frederick Charles Herrick created a distinctly art deco lion for the exhibition's official symbol as did Percy Metcalfe for the exhibition medal, Clemens chose a more subdued approach for the six seated lions he sculpted in concrete for the Government Pavilion, taking a middle path between realism and art deco stylisation.
Clemens often produced monumental works in stone to fulfill commissions as part of major British construction projects of the early 20th century.