So following May's late night 'new deal' with legally binding assurances, Geoffery Cox has provided his legal advice on that deal.
The full document can be found here: https://assets.publishing.service.go..._co..___2_.pdf
The last paragraph/point seems to be rather damning:
"19. However, the legal risk remains unchanged that if through no such demonstrable failure of either
party, but simply because of intractable differences, that situation does arise, the United Kingdom
would have, at least while the fundamental circumstances remained the same, no internationally
lawful means of exiting the Protocol’s arrangements, save by agreement." (Bold added by me for clarity).
So it would seem that the main legal assurance sought in the latest dealings - the the confirmation that the UK can legally, unilaterally, pull out of a backstop (and not be locked into it indefinitely) - has not been achieved.
Will that be the central sticking point? Will the new version be voted down today?