"The actor played spy Harry Palmer in three movies in the mid-1960s - 'The Ipcress File,' 'Funeral In Berlin' and 'Billion Dollar Brain' -- and he's keen to bring the bespectacled Cold War super agent back to life one more time."
Show Business Is My Life

I was under a lot of pressure to not bumble the reels and keep the film advancing smoothly through the trusty pair of Simplex projectors. The large, satisfied audiences gazing Caine never knew an actual grown-up was not in control.
I was pleased with my performances of "The Ipcress File," heavily determined by the not getting yelled at.
Operating the machinery without a safety net during those late nights was exhilarating, but -- hey, wait a minute! -- it meant my ride was already in bed.
I didn't mind. I had grinning achievements to ponder, walking out of the building and into more dark.
"The Ipcress File" (1965) Trailer via YouTube
Poster via Moviegoods