Henry was assigned as a Wireless Operator and Upper Rear Gunner in a crew to fly a daylight operation to attack a German cruiser docked in Christiansand harbour, on the southern coast of Norway. During the attack, the other two planes on the operation were shot down and Henry's Hampden was attacked by six ME 109s. Their Observer was killed, and Henry was wounded. Henry continued to fire as Donaldson, his pilot took them closed to sea level. The fighters continued to attack, setting the starboard engine on fire, and Henry shot down four of the six before a forced landing on the shore.
The three survivors were picked up by two Norwegian fishermen and taken to hospital in Mandal. With the aid of locals, the three of them tried to escape by using a German fighter plane that had landed nearby due to lack of fuel (the German pilot had been arrested and put in the local goal). This attempt failed and the locals were forced to give them up when the Germans arrived in town.

From his DFM citation:
"Corporal Henry, wounded at the outset of the engagement and heavily outnumbered, showed the greatest determination and gallantry, and it was largely due to his efforts that his Captain was able to crash-land the Bomber on the shore, the gallant young NCO firing his guns right up to the last moment. His complete disregard for personal safety and devotion to duty were of the highest order.
Corporal Henry displayed great courage and magnificent determination in a most gallant fight against heavy odds. His skill and judgement were outstanding in a most desperate situation."

PHU - Personnel Holding Unit