The Parliamentary Whip should be abolished. If people belong to a part, it should be because they are ideologically in tune with the other members. This should guide their vote, not the threat of sanctions.
Why does this idea matter?
I believe that the Parliamentary Whip is a threat to democracy. If you look at http://www.parliament.uk/about/mps-and-lords/principal/whips/ you will see what one does. Although I understand why they exist, surely the MPs are there to represent the people who voted for them and not the party they belong to.