http://azvsas.blogspot.co.uk/2017/12/6-months-after-election-3-resignations.html?m=1
First of all, opposition to Brexit doesn't need to involve a second referendum: Brexit was a non-binding plebiscite and moreover in the UK parliament is sovereign.
Secondly, various European countries have had referendums on Europe over the years, and they typically vote against it only to be told they need to vote again (and then they vote for it). This should be a worrying phenomenon for everyone and I for one do not want to encourage it.
Thirdly, it is far from clear what the political ramifications of such a move would be (calling for a Brexit II referendum). As it stands, May is digging herself deeper and deeper into a multi-faceted constitutional crisis, and as "one shouldn’t interrupt one's enemy when they're making a mistake" it seems May should not be interrupted repeatedly. (Corbyn has always focused on opposing neo-liberalism and austerity, to his credit.)
In agreeing to a soft border with the Republic May has committed herself to uphold all common market regulations, just with no say over them (how she is going to reconcile that with her own party is an open question). This means that should Scotland vote for independence in order to remain within the EU there would be no need for a hard border with England. As Scots are pretty much 50-50 on independence within the EU vs Union Brexit and the Scottish parliament have legislated for the Scottish government to hold INDY2 this could well prove decisive in ending the Union with Scotland.
Meanwhile in Northern Ireland the DUP have committed to reinstating the Irish Assembly and giving it a say on the border issue, thus requiring input and collaboration with Sinn Fein.
May has to somehow come up with a decent trade agreement and then get the whole Brexit deal passed through Parliament. If she cant then the UK is faced with the prospect of crashing out of the EU without a deal, which will either mean crippling economic damage or just agreeing to do everything as before without any say on any of it until we work out what else to do.
In such a situation we could well see Scottish independence finally realized, and unfortunately a destabilization of Ireland as forces there agitate for/against the same.
It seems to me that opposing Brexit should be done when it becomes clear what kind of deal May has managed to negotiate, both within Westminster and in the form of INDY2. My main fear (other than Corbyn/MacDonnell assassinations) is that this resistance somehow clashes and ends up failing (Something equating to a non-league team missing an open goal in the cup final...). In short, how and when it's done is indeed of great importance, but calling for a second referendum now is dubious at best. I'm not sure exactly what is the best way to take the Tories down, but May and her party are in a hell of a mess and have astute political opponents, a pissed-off electorate and tanking economy.
http://bellacaledonia.org.uk/2017/12/08/arlene-foster-helps-both-ways/