In April 1940 at the age of 61 Harold Ozanne was recalled for Service and was appointed as Officer Commanding the Royal Marine Engineers in the rank of Lt Col.
In September 1941 he was transferred to the Royal Marine Depot at Exton, near Exeter which was later renamed as Depot Royal Marines Lympstone.
He ended his tour in December 1943 here as Office Commanding the Depot which was responsible for training over 800 Marines at a time for the war effort.
He finally retired in January 1944 as he approached his 65th birthday
Harold's medals were donated by his wife to the Royal Marine Museum in Portsmouth, where they are on display
He died at Bishops Stortford Hospital on 1st February 1945.