This new political thriller written by Ben Brown and presented by Bill Kenwright is about the critical period in May 1940 when Britain teetered on the brink of giving in to Hitler.
The play is previewing in regional theatres prior to the West End transfer.
Clarke has said it was a challenge playing the man voted Greatest Briton: "It's challenging because people know who he is.
"They have seen him, and can still see him in footage. They can hear and see him making speeches. It's a challenge to get close to the man, but every role is a challenge and, if it's not, you shouldn't be doing it.
"I went for the voice, as close as I could get. I had to grab the audience immediately with that. If you don't, they ask: where's Churchill?"
Book Three Days In May tickets online now.
[posted by Louise, 21/09/2011]