The Literary Churchill

In a video at the Liverpool Museum (“The Power and the Glory?”), Churchill is quoted as saying that Britain, having gained prosperity by her efforts, must be prepared to defend it: “We have got all we want in territory, and our claim to be left in the unmolested enjoyment of vast and splendid possessions.” I am an American and large numbers of my fellow citizens seem to struggle with the same issue; Churchill’s words suggest an answer. When did he say or write this?