"I was a student then, a junior doctor. Just going through and living my life. I was on my way to work and this nice-looking bloke just stopped in front of me, took off his tie and said 'like so.' I was surprised and thought he was a nutter really. So, I go into work, and we're doing rounds, and then laying in the bed is the very same man who'd taken his tie off."

Martha paused for a second, and half-smiled. "I called him on it, and then he acted like he'd no idea what I was talking about, and it turned out that he hadn't. But while I was listening to his chest, I discovered something really odd.

"He had two heartbeats. I moved my stethoscope because I thought I was mental or something, and then I locked eyes with him, and he just winked."