The head of Britain's new Brexit ministry on Sunday said that EU migrants arriving between now and the country's official departure from the bloc may not be guaranteed the right to remain.
David Davis told the Mail on Sunday that he would negotiate with European leaders to secure "a generous settlement for EU migrants here now and a generous settlement for British citizens in the EU", but offered no such assurances for newcomers.
"There are a variety of possibilities," he said of plans to deal with a predicted "surge" in arrivals from the EU ahead of Britain's departure.
"We may have to say that the right to indefinite leave to remain protection only applies before a certain date. But you have to make those judgments on reality, not speculation."
Britain will have to stick to the EU's freedom of movement rules until it officially leaves, but will then have control over who stays in the country, including over those who arrived before the pullout date.
Davis has said that invoking Article 50, which would trigger official negotiations to leave the EU, should happen by the beginning of 2017. The negotiations have a two-year time limit, meaning Britain would leave by early 2019, at the latest.
The EU Commission is refusing to hold talks until Article 50 takes effect, but Davis said some dialogue was inevitable.
"We don't have to do any negotiations, just find out where their interests are," he told the paper. "(Foreign Secretary) Boris Johnson is going to the EU foreign affairs council this weekend. Are they going to say, 'Oh, I can't mention this to you?' Of course not."
Davis, 67, has been a long-time eurosceptic and was briefly Europe Minister in the Conservative government of former Prime Minister John Major in the 1990s.