He was educated at Cotham Grammar School, Bristol, then won a scholarship to Downing College, Cambridge, where he studied Biological Sciences.
After that trip he moved to Plymouth to work in the laboratory of the Marine Biological Association, researching a disease of eel grass.
There, in addition to teaching and fire-watching duties occasioned by the War, he developed his interests in lake algae begun during the Titicaca expedition.
This led to visits to the research station of the Freshwater Biological Association near Windermere, where he met his future wife.
Sir Arthur Tansley had drawn his attention to the need for a new British flora, and Tutin began a collaboration with Arthur Roy Clapham and E. F. Warburg, to write the 1591-page Flora of the British Isles, published in 1952, which quickly came to be regarded as the standard work on the subject.