The origin of "In the Bag"
Having studied politics and visited the House of Commons I was lead to beleive that the saying "in the bag" originated from a bag which sits behind the speaker of the house. For Prime Ministers question time, an MP would submit his question to the PM by placing it in the bag. Henceforth when constituents or journelists would ask an MP if they had asked the PM a question on a specific subjct they would respond, "Its in the bag". No idea on dates for this however.