The whips are a group of MPs who are in charge of party discipline. It is their job to make sure MPs on their side all vote with the party line. They are notoriously secretive about the way they work and have a reputation for using torture and blackmail against MPs. But here, whips from all three major parties tell us about their role and how it is changing. Labour Chief Whip Rosie Winterton tells us how they try to convince MPs of the merits of the argument. We learn through Conservative Whip Desmond Swayne that they are in charge of what office an MP gets, which can be used to persuade them. Under the coalition government, MPs in this parliament have voted against their party in record numbers. Don Foster, Liberal Democrat Chief Whip, tells us how difficult it is as a whip in a coalition, where there is a natural split between the two governing parties. As their job becomes more difficult, is the power of the whips in decline?