On 22 June 1940 France capitulated to Germany. Stehlík and other Czechoslovak airmen were evacuated to the United Kingdom, where they were quickly enlisted in the RAF Volunteer Reserve. Stehlík was re-trained to fly Hurricane Mk I fighter and given the rank of sergeant. He was posted to the newly formed No. 312 (Czechoslovak) Squadron RAF, where he was allocated to Yellow Flight with Pilot Officer Alois Vašátko and led by Flight Lieutenant Denys Gillam.