MPs

Not Military Police, Members of Parliament.
They are elected to represent the interests of their constituents. However, it is only on TV, and in the minds of script writers that "landslide" victories occur.
 There is always a section of the electorate who vote for one of the other candidates, and some don't even bother to vote.
So, in an ideal world, the elected MP would consider ALL their constituents before making a choice in a vote, and it is naive in the extreme to think that they will always follow the wishes of the section of their constituents who voted for them.  They should consider the other constituents, especially if they wish to keep their position in the next election.