Farage's Brexit Party has been holding rallies in Labour constituencies and hoovering up disenchanted Labour voters who want Brexit. In the referendum the vote for Brexit grew stronger as one went north. The exception was the big urban centres like Manchester. The possible outcome in the next GE is that the Brexit Party may emerge as a New Labour party.
Now that the PC liberal globalist elements in the Tory Party have been squeezed out the Tory Party has been saved from extinction. That was Boris Johnson's sole aim and purpose when he stood for PM and won against the anodyne Jeremy Hunt a dissembling Remainer. As the grounds shift the natural tendency of those Tory voters who gravitated to Farage's Brexit Party out of disgust with the old Tory Party and its perfidious Theresa May, will now likely shift back to Boris Johnson's regenerated Tory Party, a party with a very long history and a visceral instinct for survival - just so long as it sticks with the pledge to get Brexit. Farage is watching Boris like a hawk and any backsliding on the Brexit commitment by will have Farage screeching betrayal at max volume. They share a common purpose but they will not share power. Farage's strenuous efforts to capture the Labour vote make that clear.