On 21 November he was posted to Waltham to take command of 100 Squadron. On 16 December 1943, 100 Squadron received orders to attack Berlin. Holford piloted a Lancaster for the attack. The raid became known as 'Black Thursday' as 25 aircraft were lost on the raid and 28 crashed (and four abandoned as the crew baled out) in England where airfields had become fog-bound. Seeking to land at RAF Grimsby, Holford's Lancaster flew into the ground near Kelstern with only the wireless operator and tail gunner surviving.