The only reason there is any "crisis" is that the House of Commons refuses to agree to anything. Largely caused by Corbyn. Taking a hard-nosed approach to the EU is the only way to deal with them - if you don't they just walk all over you. As Yanis Varoufakis will tell you after having been the Greek finance minister and trying to negotiate with them over a bailout of Greece's financial mess. (Sensible guy - he used to be an economics professor in England and Australia and now has founded a completely different party. Why he ever joined Syriza beats me but I'm sure he had his reasons and did a better job for them than anyone else could.)
Labour cannot win. It has always relied on Scottish seats and now it hardly has any thanks to Scotland becoming virtually a one-party state under the SNP. Labour's only chance of being in government with Jezza at the helm is to form a coalition with the SNP, which both sides have absolutely said they will not do. Mind you, we can't trust that statement as being politicians, of course they will change their minds at a sniff of power.
Corbyn always was opposed to the EU, as all the Labour Hard Left were. He's now leader of a party totally divided on the issue, as it always has been (that caused the referendum in 1975) and doesn't actually have any Brexit policy. As you will see if you read their 2017 general election manifesto.
Meanwhile, unlike Labour, the Tories DO have a policy. It is a very clear policy, too. There is a deal on the table, patiently negotiated under Theresa May, and the House of Commons don't want it. The government could revoke its notification to leave under Article 50, but to do that goes against the clear vote of the British people. Which only leaves "no deal". All this is blindingly obvious to anyone with even half a brain. But obviously not to the average MP, who just doesn't want Brexit.