> But the PM in your country doesn't have unilateral authority to commit to military action, which is not the case in the big powers.
They actually do:
"Constitutional convention requires that the declaration of war or commitment of British armed forces is authorised by the Prime Minister on behalf of the Crown. Parliament has no official constitutional role in the process.[7] However, ministers are still accountable to Parliament for the actions they take.[8]"
In practice they may not remain Prime Minister for long if they tried to use those powers in a manner that parliament wasn't happy with (unlike in the US, the UK prime minister can be deposed by parliament at any time), but in the first instance that power does lie with the PM.
They actually do:
"Constitutional convention requires that the declaration of war or commitment of British armed forces is authorised by the Prime Minister on behalf of the Crown. Parliament has no official constitutional role in the process.[7] However, ministers are still accountable to Parliament for the actions they take.[8]"
https://en.wikipedia.org/wiki/UK_parliamentary_approval_for_...
In practice they may not remain Prime Minister for long if they tried to use those powers in a manner that parliament wasn't happy with (unlike in the US, the UK prime minister can be deposed by parliament at any time), but in the first instance that power does lie with the PM.