"Not exactly a groundswell (yet?), but the LibDems, the SDLP and a good few Labour MPs are willing to vote against Article 50 unless there's going to be a referendum on the final exit terms agreed with the EU."

Well of course there are a number of things wrong with that little scheme if we play according to what is stated in the Treaty of Lisbon and what Jean-Claude Juncker has clearly stated:

1: No negotiations or talks BEFORE Article 50 has been triggered. So our lads in Parliament have got the cart before the horse

2: So no final exit terms will be known until Article 50 has been triggered.

3: Once article 50 has been triggered the process is irreversible so what have our chaps got to talk about? What prats we have been to throw away our rebate and currency to shackle ourselves to the Euro?

4: If the referendum we've just had was not binding, why go through the rather expensive and apparently pointless exercise again? Salve consciences, or just the desire to waste taxpayers money?

So the Government have got to formulate in detail what we want out of our departure, then that must be debated at length in the House of Commons and reported fully in the world's press. Once that lot has been decided upon, if Article 50 is given the OK (Not a hope in Hell really - Our professional politicians have a vested interest in keeping their pathway open to the greatest "gravy train" in the world), our team then toddle over to negotiate with the EU Commission who have by now had months to counter all our points and gain maximum advantage. If our elected members of Parliament vote against Article 50 then basically Parliament has just told 17,410,742 members of the electorate to basically go fuck themselves - hope they enjoy that, because they will only have until 2020 at the outside to savour it as those 17,410,742 voters will take their revenge at the next General Election.

The vote in Parliament will be on Party lines and the Conservatives have stated that post referendum they are for Brexit respecting the result, now all the LibDems with their 8 seats + the 3 SDLP + all 56 SNP members + all 232 Labour members will not outvote 330 Conservative MPs.