The monarch has the power to dissolve the UK Parliament.That includes dissolving Parliament
No one else.
No matter how hard you stomp your feet.
This is a fact; there are no shades of gray.
"In addition to opening Parliament, only The Queen can summon Parliament, and prorogue (discontinue without dissolving it) or dissolve it.
When a Prime Minister wishes to dissolve Parliament and call a general election, he or she is obliged to seek the permission of the Sovereign to do so. For this purpose, the Prime Minister usually travels to Buckingham Palace before announcing a general election.