Last year's Brexit vote threw the futures of 3 million EU nationals living in the UK into doubt. A year on, May has promised that they will keep their rights, but only if they apply for new immigration status.
UK Prime Minister Theresa May said on Monday that her government's 17-point plan for EU citizens in the UK would lay to rest anxieties felt in the wake of Brexit.
Under the plan, EU citizens living in the UK before a certain cut-off date will be allowed to remain and apply for formal residency rights, or "settled status," after the UK formally withdraws from the bloc. They would also be likely to be required to apply for a special ID card confirming their status.
The cut-off date has yet to be decided and could threaten to cause major rows between London and Brussels.
"I know there's been some anxiety about what would happen to EU citizens at the point we leave the European Union," May said. "I want to completely reassure people that under these plans no EU citizen currently in the UK lawfully will be asked to leave at the point the UK leaves the EU. We want you to stay."
However, May added that her "fair and serious" offer was conditional and based on the UK receiving a reciprocal deal from Brussels guaranteeing the rights of some one million British citizens living in the EU.
Her plan, however, was met with jeers and heckles by opposition lawmakers in the House of Commons, while Labour leader Jeremy Corbyn described the pledge as "too little, too late."
The opposition leader accused May of using citizens as "bargaining chips."
"This isn't a generous offer," he said. "This country needs a new approach to Brexit."
Earlier on Monday, May struck a deal with Northern Ireland's Democratic Union Party (DUP) to form a ruling coalition government.
EU's cool response to May's offer on citizens' rights
The EU's top Brexit negotiator Michel Barnier responded coolly when asked about May's Brexit offer on EU citizens' rights.
Read more: Britons want Brexit clarity one year on
"EU goal on citizens rights: same level of protection as in EU law," Barnier wrote on Twitter. "More ambition, clarity and guarantees needed than in today's UK position."
Barner's response echoed the general feedback May's proposal received at the EU leaders summit in Brussels last week, namely that it was insufficient and vague.
European Parliament's chief Brexit negotiator, Guy Verhofstadt, welcomed some elements to the proposal, but warned that "a number of limitations remain worrisome and will have to be carefully assessed."
Verhofstadt said in a statement: "The European Parliament will act to protect the rights of EU citizens in the UK and defend the integrity of European Union law, including the Charter of Fundamental Rights and its enforcement framework."
What role for the ECJ?
The questions of which body will oversee the guarantee of EU citizen's rights in the UK threatens to prompt another clash between the two sides. On Monday, May reiterated her stance that citizens' rights in the UK should be overseen by British courts. Meanwhile, Brussels wants that oversight to remain with the European Court of Justice.
Another issue that could be contested by Brussels are EU nationals' rights to bring spouses with them to the UK. The offer makes clear that anyone EU national seeking to bring a spouse to the UK would be required to meet an 18,600 pound ($23,700; 21,100 euro) minimum income threshold. British citizens currently seeking to bring a non-EU spouse to the UK face similar barriers.
dm/rc (Reuters, AFP, dpa)