-
It is really dependent on a couple of factors; what the turnout of traditional true blue Tory voters is (who may not want to switch allegiance, but don't feel compelled to vote), and the level of protest voting for Reform amongst other right-wingers.
However, Reform currently lacks a charismatic standard bearer, or even a broadly recognised one. Gratingly, I think if Nigel Farage assumes the helm his branding and zealous campaigning could be enough to bring Reform level in the polls with the Conservatives. I'm not sure that's likely, however.
Latest Electoral Calculus GE prediction:
https://www.electoralcalculus.co.uk/prediction_main.html