“Eva Braun didn’t die on 28 October 1970. Instead, she changed her identity, for a second time, to Valentina Suarez. After John’s birth in America, she was forced to fake her death by you, Mr Franklin, together with Bormann, as you both thought she might prove a liability down the line.”

John Franklin turned to his father and spoke for the first time since Hembury had entered the room. “Is any of this true, Dad? I always believed she died the same year I was born.”

Richard Franklin spoke to his son as if Hembury wasn’t present in the room. “Everything your uncle and I did was done to protect you, John. From the moment you were born, we planned your path to power and it was far better you believed both your grandparents were dead. That way, you had no real ties to Argentina. No reason to ever go there.”

Hembury picked up again as he was pumped and ready to deliver the death blow. “John, even a cunning arch manipulator like Bormann failed to foresee one flaw in the plan – Eva Braun’s longevity. In a few days’ time, she will celebrate her one hundredth birthday.”

Richard Franklin’s voice roared into life, in a desperate attempt to shield the truth from his son. “That’s a lie, John. It’s a total fucking lie.”

Hembury ignored the hysterical outburst and reached inside his jacket for his iPhone. He set the video function live and held the mobile in the air. An image of Eva Braun filled the screen, and for a couple of tantalising seconds nothing happened. Then the silence was broken by the sound of an old woman’s voice. Both the Franklins spoke fluent Spanish and had no problem tuning into her Argentinian accent.

“Martin planned everything. He was a true genius … He planned our suicides and the escape from Berlin …”

For the next few minutes, no one spoke in the room. The only movement was made by John Franklin, who edged closer to the phone to gain a better look at his grandmother. Richard Franklin kept his eyes on the screen but, at the same time, his right hand edged steadily towards the bottom drawer of his desk. He slowly slid it open, without making a sound. When the video file stopped playing, Hembury detected the slight hint of a tear in John Franklin’s eyes. He put the mobile away and regained eye contact with Richard.

“Mr Franklin, you asked me before what I wanted. I’m ready to tell you.”

Franklin stared back impassively, his poker face restored.