This is the ideological link between the UK Conservative Party and the US Republican Party:
Both are captured by rightwing ideologues who always want to shrink government to cut taxes on the rich. David Cameron in the UK was that kind of Reagan “conservative”.
And just as in the US, effectively cutting taxes (austerity) makes the billionaire donors happy but alienates the voters.
So — you then have to lie to voters about immigrants and minorities to win. And then you open your party to being taken over by a charlatan and liar Boris Johnson, or, Donald Trump.
But Cameron and Reagan and their mission to help the rich and lie to the middle class are the causes.