Appointed honorary Wing Commander on 22 September 1939, in the same period, Cotton was recruited to head up the fledgling RAF 1 Photographic Development Unit (PDU) at Heston, England.
Appointed honorary Wing Commander on 22 September 1939, he greatly improved the RAF's photo reconnaissance capabilities through his experience and knowledge. In the same period he was recruited to head up the fledgeling RAF 1 Photographic Development Unit at Heston, England.