Conservative lawmakers loyal to May also warned that defeating the agreement could mean that Brexit never happens, because Parliament would halt Britain's departure rather than accept a chaotic "no-deal" exit.
Last year's Catalan referendum was deemed illegal...
Brexit has already stoked calls for a second independence bid in Scotland, and politicians have warned they could try to get this in motion if Britain crashes out of the European Union without a deal in place.
Meanwhile, the Democratic Unionist Party abstained on a number of amendments to the finance bill.
"Until it is clear. we will not be able to give our agreement", he said.
May defended her deal in an article for Tuesday's Belfast Telegraph, saying it "puts Northern Ireland in a fantastic position for the future".
May is under intense pressure from pro-Brexit and pro-EU British lawmakers opposing the divorce deal.
Sanchez has now the support of 85 deputies of the 350 seats held by the Spanish Congress, so whenever he wants to take any proposal approved, he must seek support in a fragmented hemicycle.
However Monday passed without any announcement from Sir Graham Brady, chairman of the backbench group, that he had received the 48 missives needed to trigger a confidence vote.
Vikings Defense A Decent Play Against Bears
After it happened with this weeks' game against the Vikings, it did with another contest for Matt Nagy's team in December. The Bears and Vikings also both pass block better than they run block, but their offensive lines are average at best.
A summit is scheduled for Sunday were European Union leaders from all 27 member states will give their approval to the Brexit deal.
The EU has already agreed that no deal on the future EU-UK relationship can apply to Gibraltar without an agreement between Britain and Spain.
The small peninsula, a British territory since 1713 and known to its 30,000 residents as "the Rock", is a major point of contention in Anglo-Spanish relations.
Spain will vote against the European Union's draft Brexit deal on Sunday unless it is modified to make clear that the future of the disputed British territory of Gibraltar relies on talks between Madrid and London, Prime Minister Pedro Sanchez said.
Spain said last week that it welcomed the inclusion of a protocol on Gibraltar in the draft Brexit agreement, but Mr Borrell said that the document introduced "a certain confusion" on the issue.
Such an interpretation is entirely unacceptable for Spain, which wants absolute clarification that any future talks on Gibraltar will be between Madrid and London, and no one else.
Few observers believe the deal will win the approval of the British parliament next month when lawmakers are scheduled to vote on it formally, as all opposition parties have formally come out against it.
The parliamentary arithmetic looks daunting for May, and if lawmakers reject the agreement in a vote expected next month, the United Kingdom would face a political crisis, with Brexit day looming.