Hopgood joined the
Royal Air Force Volunteer Reserve in 1940, qualified as a pilot in February 1941 and earned his commission in 1942 when he was promoted to
flight lieutenant. October 1942 saw him awarded the
Distinguished Flying Cross after completing 47 operations, and a
Bar to the award in January 1943. His initial service was with
No. 50 Squadron, where he completed his first tour before being posted to a training unit. While in service with
No. 106 Squadron, Hopgood participated in the air raid on
Gdynia in August 1942 and the daylight raid on
Le Creusot in October of the same year. It was during the Le Creusot raid that he made a low level attack on an
electrical transformer station from 500 feet.
Dambusters Raid Gibson selected Hopgood as his deputy for the attack against the
Möhne Dam. While awaiting take off Hopgood spoke with
Dave Shannon, telling him that he had had a premonition that he would not survive the mission. Gibson responded to the premonition with, "Hoppy, tonight's the night; tomorrow we will get drunk". The aircraft was fatally damaged and Hopgood remained at the controls, gaining height to allow his crew to bail out. Rear gunner,
Pilot Officer Tony Burcher, remembered hearing Hopgood say; "Get out you damn fool. If only I could get another 300 ft. I can't get any more height". John Fraser and Tony Burcher jumped and were made
prisoners of war. However, the already injured John Minchin who also bailed out did not survive. AJ-M crashed in a field near Ostönnen, 6 kilometres (3.72 miles) from the dam. The bodies of Hopgood, Brennan, Navigator Kenneth (Ken) Earnshaw from Bridlington and Gregory were found inside. Hopgood is buried at the
Rheinberg War Cemetery (Coll. grave 17. E. 2-6). ==Popular culture==