Have they no intention of going ahead -just using this threat to cause waves?
Labour did have in their manifesto an intention/promise to protect democracy through tightening up the rules around donations, but the suggestions being touted wouldn't stop Musk being able to donate close to £100m. E.g. UK companies can only donate a max up to their profits of the last 2 years - which would stop UK shell companies being set up simply to donate money.
Interestingly, over 50% of the population would be in favour of implementing a cap on donations, and almost 20% think there already is one (there isn't).
To put the touted £100m into perspective, that would be more than the total donations to all parties in any single year.
Suppose they did go ahead and weren't stopped is the destruction of the Tory party the most they could hope for?
In terms of vote-share, yes, most likely this would be the main outcome. Reform might become the main opposition in terms of vote-share, if enough Tories jump ship.
They might also steal the "protest votes" that currently go to Labour or Lib-Dems, but that would depend on the appeal of Farage, and how far right-wing the Reform UK set themselves up as.
But in terms of Parliament, it might really only serve to give Labour a higher majority on an even smaller share of the vote, as they split the Tory vote even more. So I could see many Labour MPs winning in previously Tory-held areas while winning just 30% of the vote, with Reform at 25%, Tories at 22%, Lib Dems 18%, others 5% etc. That's the joy of our FPTP system... huge majorities in Parliament from a minority of votes. :/
And it will increase calls for a change to the system to a Proportional Representation, which Labour, being the main beneficiary of the rise of Reform, will clearly refuse.
And then there's the question of whether Reform and Conservatives make any alliances so as not to split their vote - agreeing up front to join in coalition in the inevitable hung parliament. This is quite likely as well, although whether Farage's ego would allow him to if he's not to be PM in such a situation, who knows!
Can Trump act as the sidekick and attack the UK with heavy tariffs to damage the government?
Sure. But this would be seen as clear foreign interference in the UK election, at least if done for those purposes, and would greatly worsen UK/US relations - and likely EU/US relations as well. Afterall, if the US want to involve themself in UK elections, surely France would be next (the far-right are a bigger threat there than in the UK), and Germany (and he seems to be courting the AfD at the moment) , or Italy etc. I would envisage sweeping legislation to prevent such interference in all geographies if it got too obvious.
If the tariffs are part of wider levy on many/all other countries, e.g. EU as well, then they'd be brushed off as just Trump being Trump.
Also bear in mind that the next UK election should be in 2029, which is after Musk, and his sidekick Trump "peacefully" relinquish power. So if the next person has any sense, such tariffs should be removed by the time of the election.
But also we would simply react with our own tariffs on US goods, as we did last time (Jack Daniels, Levi's, Harley Davidson etc). It would damage both economies, us more than the US from this specific tit-for-tat, but other countries would undoubtedly be doing the same, thus impacting the world economy adversely. Not that Trump and his billionaires would care too much, as long as they get their tax-cut during all of this.
One must also look, with regard Musk, how he uses X to promote what he wants, and then also whether he can persuade other media companies to become the FOX of the UK - e.g. GB News - notwithstanding our watchdog's scrutiny.
