"In a plea to both main parties, however, Johnson called for an honest acknowledgement that large swathes of the electorate would have to pay more tax if incoming ministers wanted to improve public services.
“I characterise it as quite scary, actually,” Johnson said. “If you look at the OBR at budget time, they were essentially saying that on the set of assumptions then, debt would be stable at the end of the five-year period. That is in a world in which we’ve had the biggest tax increases in living memory and completely implausibly tight spending plans, post-election. Things have got worse since then.
“My plea, in a sense, is that it would be really quite helpful if [both parties] could be open about the scale of the challenges … The part we’re not going to get any honesty on, I don’t think, is on tax and spending."
It isn't just tax cuts he's worried about. It's financing public spending.