I believe you have got this fundamentally wrong Nick. Parliament gave the people the power to take the decision whther to leave or remain. The people decided to leave. No if, buts or conditions.
Parliament then voted on and enacted legislation to invoke article 50, and leave on 29th March this year. No ifs, no buts, no conditions.
Most of them did this because their constituents voted for it, not because they believed in it.
Ken Clark was the only Tory to vote against the withdrawal act, so he is the only one who has any kind of right to take the stance he has taken.
But the point is, when they gave the decision to the people, and enacted legislation on the result of that, they effectively suspended the representative element of Parliament in this matter.
The situation is (and was always understood by most people imo) that the Govt gets some kind of deal. If that deal isn't acceptable, then we leave regardless.
Once the dust had settled, those who don't actually believe in the right of the people to take the decision, or even the legislation they voted to enact, started making mischief, muddying the water, frustrating the process, hoping to cause so much confusion theat the whole thing will die a death.
It might happen, but if it does, whats left of our democracy dies with it.
That is why I believe that if they make us vote again, everyone who believes in democracy, whether a leaver or remainer in the first vote, must vote for leave, to keep our democracy alive.
Im gladdened to know that several diehard remainers of my acquaintance completely agree with me.