Originally Posted by Ancientgeezer
The right to dissolve Parliament was surrendered with the Fixed Term Parliament Act of 2011 which was one of the prices that had to be paid by the Conservatives to get the Lib-Dems into coalition. The Sovereign MUST appoint as Prime Minister a person who "commands the support of Parliament"-- in other words, has a majority. The right of the Sovereign to wage war or appoint military chiefs has not existed since 1689 and 1838 respectively.
Giving up these powers removes an implicit safeguard in the constitution that may one day be needed. It is theoretically possible that one day a totally unscupulous leader of a majority party will decide to sieze permanent power, the power of the Sovereign to protect the people is no longer in force, so a King Carlos style resistance to a coup or a Australian-Governor-General style sacking of an incompetent and rascally government and replacing them without an election could no longer be acomplished.
I forgot about the fixed term act
But the Sovereign can appoint who ever they want , whether they win the election or not. It's a convention to appoint the leader of the party with the most seat, not necessarily the majority. In the first election in February 1974 the Harold Wilson did not hold a majority, the majority of the parliament did not support him but he was still appointed as PM.
Declarations of war are not managed by the royal prerogative, only the ability to send troops/any military action requires a vote through parliament. Technically the monarch can still declare war, but cannot send troops if parliament does not vote in accordance with it. Its the power to issue empty threats really.
And I agree with that last statement of yours.