'I would like to express my sincere thanks to the men who are going to execute me': Found after 100 years, the letter from the first German spy captured in WWI to the Guards in the Tower of London | Mail Online

'I would like to express my sincere thanks to the men who are going to execute me': Found after 100 years, the letter from the first German spy captured in WWI to the Guards in the Tower of London | Mail Online