Quote Originally Posted by Banquo's Ghost
Have you a link to that?

As far as I recall, he has agreed to allow Parliament a prior vote (and to be bound by its decision) should there ever be a need to declare war - but that's his choice only. In my understanding of the constitution, he cannot give up any aspect of the Royal Prerogative because it is not a power he has unto his office. The power belongs to the Crown, and as PM he merely exercises it on her behalf (by advising Her Majesty to go to war).

Thus a future PM is not bound by his decision.
I don't know, he's also said he's going to hand over the power to create Bishops to the Church. That probably has something with the previous holder of his office being as Catholic as Charles II.