The regiment spent the spring and summer of 1944 training in readiness for the invasion of Europe. In September the regiment took part in Operation Market. Taking off from RAF Fairford on 17 September Thompson, most of his headquarters staff and two of the regiment's three batteries and his men landed by glider at west of Oosterbeek, Arnhem. Shortly after the landing Thompson is recorded as "C.O. "kicking" because there were no targets to fire on, he said we might just as well have come on the next day." The following day with the arrival of the remaining battery the regiment moved to positions around Oosterbeck church to support the attempt by 1st Parachute Brigade to break through to Arnhem bridge. The attack by 1st Parachute Brigade failed and troops from the four infantry battalions started falling back towards Thompson's position. Thompson left his headquarters and went forward to try and get the retreating troops into defensive positions. Thompson organised about 400 men into positions along the road to protect the artillery positions and to block and German advance down the road, placing these men under the command of the most senior officer he could find, Major Robert Cain of the South Staffordshire Regiment, Thompson returned to his headquarters to report to his commanding officer, Brigadier Philip Hicks. Hicks sent Major Richard Lonsdale of 11th Battalion, Parachute Regiment to assist Thompson. Thompson placed Londsale in command of the Parachute Regiment battalions while he took command of the South Staffordshire men in addition to his own regiment and the men of the Glider Pilot Regiment. The whole force was designated "Thompson Force" by 1st Airborne Divisional Headquarters.