The Oscar-winning actor reveals how a TV film on his grandfather’s years as a PoW raised tough moral questions

For Mark Rylance, the opportunity to track down the truth about his late grandfather’s wartime life seemed a way to get closer to the memory of a loved family member. But delving into that past has also accentuated a painful gulf between them.

“I knew him very well, but there was a lot I hadn’t heard about, though I’d suspected some of it,” the Oscar-winning star of Dunkirk and Bridge of Spies told the Observer before the broadcast of a television documentary that will follow his journey of discovery. “I understand his feelings about the Japanese better now, although I can’t agree with them.”

I don't think grandfather would agree with everything I say, but I think he would be interested