You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Prime_minister

Context:
The term prime minister in the sense that we know it originated in the 18th century in the United Kingdom when members of parliament disparagingly used the title in reference to Sir Robert Walpole. Over time, the title became honorific and remains so in the 21st century.

Question:
Who was referenced as prime minister in a negative manner when the term was first used in its modern sense?

Sir Robert Walpole