Answer:
Members of Parliament, whilst in the House of Commons, may not refer to each other in the second person, but must always use the third person. Traditionally, Members or Parliament do not refer to each other by name, but by constituency - "the Honourable Member for [constituency name]. If the Member of Parliament is also a member of the Privy Council, the address would be "the Right Honourable Member for [constituency name]. It is not always practical to expect Members to remember the constituency names of all of the participants to the debate, so referring to each other as "My (Right) Honourable Friend, Lady or Gentleman" is accepted.