If Theresa May wants out of Brexit (and there's little evidence she does) but if she did, the best way of doing it would be under the guise of national security
She needs to pull Alex Younger in and ask him to write her a secret memo that implicates the unofficial leave campaign having colluded with Russia. Remember Robert Mueller has named Nigel Farage as a person of interest whom he wants to talk to (would be amusing to see Farage hiding behind the European Human Rights Act to avoid going to America incidentally). Basically though, if she implicates the unofficial campaign she shields many of her own MP's, whilst casting Farage, UKIP et al as traitors. It would be a very brave (or incredibly stupid) bunch of MP's who were prepared to put their hand in the fire for Farage under these circumstances. It would also cut off UKIP at a stroke as life raft for would be dissident Tories, who would be forced to fall in line, and especially if the memo alluded to evidence provided by foreign allies (code for CIA)
The whole thing is a gigantic accident anyway which has its roots in David Cameron (the worst Prime Minister in history, so hang your heads in shame all those of you voted for him) telling the BBC's James Landale that he wouldn't seek a third term. If Cameron had kept his mouth shut, the Boris Johnson would have campaigned for remain, and they'd have won. The only reason Boris jumped the way he did was because he realised that in order to become PM he needed to expand his support base beyond the 40 or so MP's he could muster to get himself into the final two of a leadership contest. If Boris could do this, then he'd stand a chance when his candidacy was put to the wider party (probably against George Osborne). Boris duly realised that the only bloc within the parliamentary party capable of propelling him over the necessary threshold was the Eurosceptic wing and so he joined them in the hope of getting in the region of 120+ votes some 18 months later. He figured remain would win, but if he campaigned for leave, and was seen to have played a good innings, he could lever that support into his leadership bid. He got it wrong though. He completely cocked it up. Instead of losing, he won. Suffice to say, when the leadership battle was consequently brought forward, the more savvy sceptics who recognised what he was doing duly stabbed in the back and dropped him the moment he'd served his purpose and became expendable
The whole thing is a farce of accident, driven by one mans ambition and chronic miscalculation