In Hitler's Secret War: The Nazi Espionage Campaign Against the Allies by Charles Whiting he mentions on page 195 that at the end of the war Col Hermann Giskes was being interrogated when he recognised the voice of a man, Jack Hooper, who had betrayed his fellow Dutch resistance members to the Germans and then returned his allegiance. He was Dutch but had taken British nationality. After Giskes had identified the man he asked what would happen to him he was told the man had been hanged.
Because the name was not in the London National Archives I sent an e mail to Frans Kluiters who has a list of Dutch agents on his website and received the following reply
"I am sorry to disappoint you, but William (NOT Jack) Hooper was no traitor. West called him (in MI6, p. 241) so, but after some twenty years of research I have come to the conclusion that this is not the truth. William (Bill) Hooper worked for MI6 all along. He has been portrayed as an agent working for the Germans, but this was a double cross operation. During the war he switched from MI6 to MI5, and died only in the seventies."
He does not mention Hooper's originally being Dutch. Is it possible that there were two agents with the surname Hooper? Can any one shed any light on the difference of information please?