The "left" call Tommy Robinson a fascist for a number of reasons, but one of the more obvious ones is that he was part of the British National Party, a fascist organization. It is hardly a controversial thing to say.
And the problem with the immigration debate is that we are relying on it to paper over the cracks caused by our ailing birthrate. Even if nobody objected to high immigrations, its an unsustainable solution. We need to figure out a way to either boost the birth rate or revolutionize society.
The typical right wing (like the Tories), in particular, have no interest in doing this. For one, it's not good for business but - likely more importantly- it isnt good for them electrorally (because if we cut immigration the first thing on the chopping block will have to be the state pension, and that'd be suicidal for a party that relies on the support of older voters).
As to what Reform are doing, I have no real idea (I'm not certain they do either).
They're messaging is focussed on stopping the boats, and illegal immigration - which accounts for less than 5% of immigration. They've now put forward something of a plan, and it involves us saying goodbye to our human rights and leaving various international treaties. I, for one, would not want to give up my rights for very little gain, and I suspect that leaving all sorts of international treaties will have negative diplomatic and trade reprocussions for us. We'll be poorer, have fewer rights, and be an increasingly irrelevant little country.
I don't believe they'll cut legal immigration in any significant way but, assuming they form the next government, I guess we'll find out. If they do, then the poor and the elderly will take the greatest hit but my guess is that they'll do jack shit about cutting net immigration and then their voters will start whining about Reform betraying them, just as they whine about the Tories now, then will vote for the next snake oil salesman promising them a magic uniform.
Of course, none of this is helped by the absence of meaningul solutions from the Left, who are barely tinkering around the edges of the issue, but I don't think they're actively trying to fuck over the average Brit like Reform are.
I'm not looking forward to the Reform electoral win I suspect is coming, nor the dire consequences for the country, but I am just about petty enough to be looking forward at the look on Reform voters' faces when they realize they've been played yet again.