Several Government ministers had suggested Wednesday would be the cut-off for migrants to come to Britain and claim full rights, but Mrs May went against them, insisting the deadline date had to be part of the negotiations.

Instead, Mrs May will tell the House of Commons that she will fight as hard for EU migrants as she will fight for everyone else in the UK.

She will say: “When I sit around the negotiating table in the months ahead, I will represent every person in the whole United Kingdom – young and old, rich and poor, city, town, country and all the villages and hamlets in between.

“And, yes, those EU nationals who have made this country their home. It is my fierce determination to get the right deal for every single person in this country.”