Parliamentary Motions and Yesterday's debate
Yesterday's debate demonstrated the relatively counterintuitive nature of parliamentary procedure. We had the movement of the "previous question". This did happen in the last parliament. Once.
It wasn't very clever to do this as it merely had the effect of truncating debate. If it gets moved too often we will find that the rules are changed to prevent this.
The most important point is that only a limited range of parliamentary motions have an actual effect. Motions relating to statutory instruments have an effect. Those on european scrutiny issues have a partial effect, but are in fact not binding as the ministers can make decisions in the European Council before such a motion passes. Motions that affect the House of Commons (order of debate, suspending or expelling members, standing orders, committees etc) do have an effect. Those which are in conjunction with a finance bill also have an effect.
However, a motion that says "This House instructs the Government not to extend the European Arrest Warrant" does not actually have any effect on the government ... unless ... the government agrees in advance that it will have an effect. However, a motion that says "this house shall now adjourn" could bind the government on an issue such as the EAW, but only if the government says that it will.
Hence we are actually in a situation where what the minister says is more important than what it says in the motion. That is why yesterday's debate came across so badly.
There is, of course, an issue about having a single vote on all the Justice Issues. That is of course the normal way in which the executive (government) limits the power of the legislature (house of commons) to control its behaviour.
The reasoning behind the issue of what decisions have force lies in the willingness of the house of commons to enforce decisions. With the courts the use of "contempt of court" enables court orders to be enforced. "Contempt of Parliament" has the same effect for parliamentary orders. However, it is now rarely used.