Brexit: Boris Johnson is fighting on two fronts

Boris Johnson cares very much about forcing the prime minister to ditch her carefully crafted Chequers compromise on Brexit.

Again and again he has argued that it will leave the UK at the mercy of the EU, trapped in purgatory, humiliated.

He simply refuses to accept that the UK government and the EU have done all they can to find a way around the Irish border question. Very few agree.

Government sources are adamant the only way through is Chequers.

But the former foreign secretary claims the UK could easily and almost painlessly find a way of agreeing a looser-style, "super-Canada" trade deal with Irish border conundrum resolved.

But Boris Johnson also cares about Boris Johnson, and Boris Johnson's future.

Four times I asked if he would rule out challenging Theresa May for the leadership.

Four times a clear answer came there none.

He said instead it was his duty to speak up for what he believed in - and that he would keep going for as long as it takes.

It is no secret that he still wants and believes he has a shot at Number 10.

And having turned down interviews for several months after his departure from government, speaking out today on the eve of the Conservative conference outwardly appears designed to stir as much trouble as possible.

Mr Johnson is adamant, of course, that what he is really involved in is trying to change Number 10's policy, rather than trying to shove Theresa May out.

But while he is fighting for his vision of Brexit, he is also fighting for his own place in the Tories' future.