No the House of Commons would stop him. Unlike the USA, countries with governments based on the Westminster system, such as Australia, NZ etc don't give the Prime Minister this type of unlimited power.
https://en.wikipedia.org/wiki/Westminster_system
I don't think the two systems are fundamentally different. If a British PM has a Commons majority and retains the support of their own party, they can basically do whatever they like.
Conversely, if Congressional Republicans wanted to stop Trump, they could pass legislation stripping him of much of the power Congress has delegated to him (and override any veto), they could pass a joint/concurrent resolution censuring his policies (and even calling for his resignation), they could begin impeachment proceedings, they could refuse to pass the budget until he gives in to their demands. (They may well not do any of these things – but if they don't, it is because they don't want to, not because they lack the power to.)
So I'm not convinced the US system and the UK system are fundamentally different here. Both give the executive utterly vast amounts of power. Both give the legislature the ability, by somewhat different routes, to remove the executive.
> I don't think the two systems are fundamentally different. If a British PM has a Commons majority and retains the support of their own party, they can basically do whatever they like.
The difference is that a PM has no independent power; they don't just need a partisan majority in the Commons, they need the confidence of the majority of the Commons.
The President has independent power, and is not subordinate to the Congress the way the cabinet (including the PM) is to the Parliament in a Westminster system.
Strictly speaking, the British PM's legal power comes not from Parliament but from the Monarch - they are a minister of the Crown, first in rank among the Lords Commissioners appointed to collectively exercise the office of Lord High Treasurer, one of the Great Officers of State. Now, as a matter of longstanding convention, the Monarch will appoint whoever commands the confidence of the House of Commons-but that convention is nowhere enshrined in law.
Turning to the US, under the US Constitution, Congress is arguably the most powerful branch, since Congress has the power of impeachment to remove the President and judges (including Supreme Court Justices), whereas neither the President nor the Supreme Court have any corresponding power to remove Members of Congress. Congress can impeach Trump but Trump can't impeach even the most insignificant Representative.
The queen is a figurehead and doesn't get involved in politics - the point being that she doesn't fiddle with parliament's politics, and they don't cut her out of the picture. Been that way for centuries.
Here in Australia, the picture is similar. The Governor General (queen's representative) is the ceremonial head of state and can dissolve government prompting new elections, but can't direct government to a certain course of action. Dissolving government is done when it's blocked, and almost always at the request of the current head of government. However, if the Queen tried to start influencing local politics, the GG would be renamed 'president' and she'd be cut out of the picture.
Basically, the Queen maintains her power by not pissing off whichever rabble is currently in power in the parliaments of any of her countries.
> But you implied just earlier that she has no power.
She has the power to divide her time among several palaces, have lots of servants waiting on her night and day, have Prime Ministers and Presidents lining up to dine and chat with her, have the Royal Air Force fly her in luxury wherever she wants to go, etc, etc, etc... basically more power than you or I will likely ever have. She has all the power she needs.
But in terms of her formal legal/political power – on paper she has enormous power, but she only retains that power because 99.999% of the time she does whatever the politicans tell her to do. (If she ever started refusing to obey them, they would take all that power away from her very quickly.)
However, in the very rare circumstance of a constitutional crisis, she does actually have some real political power. Consider something like the 1975 situation in Australia – if something similar were to happen in the UK, she would have real power to decide what course of action to take.
The GG in Australia has the power to dissolve parliament, yes. This has only been done once (that I am aware of) and that was when the sitting government lost control of parliament and could no longer pass the laws required to pay the bills. The GG approached the leader of the opposition and asked if he was able to gain control of the house of representatives and start government working again.
There has been a lot of speculation about the legality of this event and it would be a very brave Prime Minister who would allow things to go this far again without calling an election and an even braver GG who would not politely point out to the Prime Minister that he was behaving like an idiot, accept he'd lost control and let somebody else get on with running the country.
The GG has only dissolved government without PM's request once, but if supply is blocked in Parliament for the same act twice in a row, the PM can request the GG dissolve parliament in a double-dissolution. This is what happened with our last federal election - some random act, I can't recall, was blocked twice by the opposition and minority parties. Both sides thought they'd win the election, so they were happy to dissolve over a relatively minor issue.
Basically the GG is there to keep parliament ticking over, and not descend into the madness of the last six years in the US where the chamber is eternally deadlocked (party 1 head of government against a party 2 chamber). It's bizarre how many ways the US has to stall its government (eg filibustering, debt limit, etc), and how few to ensure it keeps ticking along...
She has no hard political power and can't direct politics, but she has soft power in that she's a queen and people listen to what she says or try to curry her favour; the soft power of a ceremonial head of government. It's a complex picture. Oversimplifying quite a bit, if parliament were to 'cut her off', everything with "royal" in it would become "federal".
Curiously, they'd actually lose on the deal financially if they got rid of the royals - the UK government manages the royal estates because of a deal back in the day, and they bring in more money than they lose (before even getting to tourism). The estates would revert to the family in such an event, as I understand it.
Which party establishment? What if UKIP were to win a general election? Unlikely to happen, surely-but almost everyone said the same thing about President Trump.
I'm pretty sure the answer is "No".