I suggested this weeks ago, we are leaving the EU and it is important that unity is shown in obtaining the best possible terms.

The main sticking point is "Free movement", everything hinges on that, a red line for the EU....they cannot allow associate membership or any other get out unless we accept "Free movement" and we have realised that our infrastructure and public services simply will not stand the additional numbers arriving here.
We have also begun to realise the societal problems involved in a mass influx of other cultures and religions with the associated terrorist implication.

Mr Corbyn has always been anti EU and if he is indeed a statesman, he will use his present popularity amongst the young to make these negotiations end positively for Britain.
He could ditch his principles for short term political gain, but I think that would prove counter productive for himself and the UK.