The 81-year-old, most famous for his Oscar-nominated performance as FAGIN in the 1968 musical, claims he could have been just as successful as Caine if he had stayed in the US instead of returning to the UK.
He says, "If I'd been really dedicated to it, I would have stayed in Hollywood when I was there, getting scripts through the door for breakfast, tea, dinner, having meetings all the time.
"If I had stayed, I think I would have had a film career of some stature but the day after the Oscars I came back to England to do a play for Anglia TV. Because I was patriotic! Mad fool!
"I wanted to do it for England so I could come back and found nobody really cared. I didn't understand the business enough.
"I should've done what Michael Caine did and taken everything that came along."