Theresa May is being urged to impose a "cut-off date" for people to settle permanently in the UK
Britain could face a "surge" in migration from EU nationals rushing to come in before restrictions are imposed, MPs have warned.
The Home Affairs Select Committee is urging Theresa May to impose a "cut-off date" for them to settle permanently in the UK to avoid a spike in applications.
In a report published today, the MPs say moves to restrict immigration - as expected after Brexit - will invariably lead to a sharp rise in numbers before the deadline.
Mrs May has refused to guarantee the rights of the 2.9 million EU nationals currently living and working in Britain, saying she will wait until other countries guarantee the same rights for British citizens.
But Keith Vaz, who chairs the committee, said clarity was urgently needed.
He said: "The biggest issue relating to Brexit is migration. There is a clear lack of certainty in the Government's approach to the position of EU migrants resident in the UK and British citizens living in the EU.
"Neither should be used as pawns in a complicated chess game which has not even begun. We have offered three suggested cut-off dates, and unless the Government makes a decision, the prospect of a surge in immigration will increase."
His committee has suggested three possible cut-off dates.
One is retrospective - the date of the referendum, a month ago; the second is when Britain triggers Article 50 - the official exit process which is expected early next year; and the third is the date Britain eventually leaves the EU two years after that.
The cross-party group of MPs is calling for EU citizens currently in the UK to have their right to reside here guaranteed.
As an initial step, they suggest EU migrants should have to register with their local authority or provide a National Insurance number to ease the transition after Brexit.
Brexit Secretary David Davis has already suggested the government is considering introducing a deadline if there are signs of a "surge".
The rights of EU citizens are likely to form a key part of the Theresa May's discussions with EU leaders this week, beginning with a visit to see Italian Prime Minister Matteo Renzi in Rome today.
She vowed last week that levels of net migration - which reached 333,000 at the end of last year - will be brought down to tens of thousands but said this would "take some time" to achieve.