Labour’s policy and frequently stated position is for a confirmatory vote on any deal.
Whatever Corbyn’s position in the past regarding the EU (and this is disputable, Corbyn made more appearances for Remain than any other UK politician during the referendum campaign, despite not even being the official Labour campaign leader c.f Alan Johnson), it doesn’t even matter anymore even if it ever did.
Plus. Any argument against a confirmatory referendum after all the issues raised by the previous one and it’s subsequent consequences will be a difficult one to make.
On an earlier point re the anti Iraq war demos and the subsequent utter disaster for not only for the loss of Tony Blair’s credibility but also the deaths of possibly half a million people?
You have a lot more faith in the labour party than i do, their brexit policy has been about as clear as mud from day one due to a euro-sceptic leader and them desperate to occupy the middle ground of both leavers and remainers without satisfying either.
It is true that no, the Iraq War protest did not stop that war. On the other hand, Parliament hasn’t voted overtly in favour of military action since (the times that it has have often been retrospective, which always makes things tricky.) And a large number of folk were affected by that event and are now mainstays of antiwar movements and they probably wouldn’t have been had it not happened.
Likewise, I’m willing to bet that there were more than a few future MPs (and possibly even a PM!) somewhere in that crowd yesterday who wouldn’t have dreamed of that sort of future otherwise. Certainly I think it’s fair to say that perhaps one of the more ironic outcomes of the last few years is that the UK now has perhaps the largest and most active proEU groups in the whole of Europe! They are not going to sidle off into a corner and die.