"I appeal to all Britishers to answer this call to arms for the defence of all the principles that we Englishmen have been the first to proclaim in the world"

The quote by John Amery acts as a call to arms to all people who identify as British to come together in defence of the concepts that have been developed by England as a country. The individual is interesting the sense of nationwide pride and motivating others to collaborate in the effort to protect these concepts. The phrase "call to arms" recommends a time of dispute, and the individual seems recommending that this dispute or danger should be met unity and strength. By proclaiming that these concepts were developed by Englishmen, the person is interesting a sense of history and heritage that might serve to encourage individuals to action.