What is the fine-grained topic of the following text: Creative head, Peter Silk said: "It's always an honour to be asked to design Royal Mail stamps but we're particularly excited about this project where we have worked on two complementary sets as well as the associated collectors’ products.” “We believe this commemorative stamp issue will be valued by anyone with an interest in Britain’s nautical history, its development as a trading nation or the essential part played by the Merchant Navy during the Second World War,” said Catharine Brandy, design manager for stamps and collectibles at Royal Mail. Only return the topic.
Designing commemorative stamps depicting Britain's nautical history for the Royal Mail.