Theresa May said to make a public statement that UK won't agree to being trapped in customs union permanently

This according to sources citing by Guido Fawkes

Still unconfirmed at this point but if this is true, then it raises the odds that the UK and EU will be unable to reach a compromise on the backstop agreement. The UK Cabinet discussed the issue overnight and reportedly came to a conclusion that they want to put a time limit on leaving the customs union but the EU continues to stand their ground in that they want to leave it open-ended.

That led to reports this morning saying that if May does accept the EU's terms, she won't be able to win over support from parliament as ministers are dead set against an open-ended period for leaving the customs union.