MEPs are holding a debate on Brexit, April 5, but have already declared that the four pillars of the EU — the free movement of people, goods, services and capital — are inviolable. They agreed that the rights of EU citizens should come first in any negotiations and that their status and rights should be subject to the principles of "reciprocity, equity" and "non-discrimination."
In a sign of the tough stance, the remaining 27 members of the EU will take on Brexit talks; the MEPs said there can be "no trade-off between security and the future economic relationship," according to a statement.
The security issue is critical, as it formed part of the letter sent by UK Prime Minister to Donald Tusk, the EU Council president, in which she said Britain's strength in security, intelligence and counterterrorism could be a bargaining chip in the negotiations.
"The United Kingdom wants to agree with the European Union a deep and special partnership that takes in both economic and security cooperation. To achieve this, we believe it is necessary to agree the terms of our future partnership alongside those of our withdrawal from the EU," Theresa May wrote in her letter to Tusk.
"We want to be able to agree a deep and special partnership, taking in both economic and security cooperation, but it is also because we want to play our part in making sure that Europe remains strong and prosperous and able to lead in the world, projecting its values and defending itself from security threats. And we want the United Kingdom to play its full part in realizing that vision for our continent," May wrote.
Opening the debate, April 5, European Parliament President Antonio Tajani said:
"Parliament's vote will be decisive for the final outcome of the conditions for the UK's withdrawal and for future EU-UK relations."
"The recent terrorist attacks make it clear that all European countries will need to continue working closely with each other," Tajani said, referring to the need for continuing cooperation on security and intelligence.
The European People's Party (EPP) — led by Manfred Weber — made it clear that the overriding principle behind the talks would be the protection of EU citizens' rights and freedoms.
"Europe's citizens come first. The EU is not for sale. When necessary, we are able to change trade routes and reorganise production chains. But we will never allow the division of our EU citizens into first and second-class citizens! If the UK wants to take EU citizens hostage and threaten them with expulsion during the negotiations, we will not give our support to a trade agreement with the EU," the EPP Group said.