Free movement will end when Britain leaves the European Union in March 2019, the Immigration Minister has said.
Brandon Lewis said freedom of movement was one of the "core principles" of the EU, and that a new immigration system would be in place when Britain formally departs the union - two years after Article 50 was triggered.
He told BBC Radio 4's Today programme: "Free movement of labour ends when we leave the European Union in the spring of 2019 - we're very clear about that."
Asked why free trade and single market access would not also end then, Mr Lewis said: "There's a period of negotiation we're going through with the European Union at the moment, but we're very clear that free movement ends - it's part of the core principles, the four key principles, of the European Union - when we leave."
Pressed on whether it was a red line to end free movement in March 2019, he said: "It's a simple matter of fact that the four key principles of the European Union include free movement - we won't be a member of the European Union when we leave."
His comments came after Home Secretary Amber Rudd announced she will commission the Migration Advisory Committee (MAC) to carry out a detailed analysis of the role of EU nationals in the UK economy and society.
Mr Lewis said: "There will be a new immigration system in place from the spring of 2019 and that will be outlined in the Immigration Bill that will go through Parliament next year."
He also told the programme that it remained the Government's "long-term aim" to bring immigration down to "sustainable levels", but did not say when that would be achieved.
"(It is) our determination to see net migration fall to sustainable levels and we think that is around tens of thousands - it's something we've had and continue to have as our long-term aim."
Mr Lewis would not confirm if the target would be reached in this Parliament, and said: "If this was an easy thing to do we would have already done it.
"We cannot, people know, control our net migration levels fully until we leave the European Union."
Senior Labour backbencher Frank Field said he thought Mr Lewis's comments were "alarming", and told the same programme: "I genuinely don't think voters are looking for a cut-off point and will judge the Government accordingly.
"(Donald) Trump won in America on immigration - not because most people believed he would build a wall, but he convinced people that he was serious about trying to cut the numbers of immigrants no matter how long it took and I think that's where the British electorate is and that's where the Government ought to start to begin its negotiations."
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Ms Rudd later rejected any suggestion of a "contradiction" between Mr Lewis's comments and her own desire to avoid a hard Brexit.
Speaking during a visit to a Border Force patrol ship in Troon Harbour, on the west coast of Scotland, Ms Rudd said: "When we leave the EU, which will be in March 2019, the current freedom of movement will obviously end so what we'll need is a new system and we've said that that new system will have a proposal whereby new EU workers coming here will need to register.
"We will need that grace period for a while before the full changes come in, which is what we're consulting on with the MAC.
"The MAC have been asked to give us the real evidence about the value of EU migration to the UK because we know it has been hugely valuable and we want to make sure that the changes we put in place are evidence-based."