THERESA May has delivered a message to the three million EU citizens living in Britain, saying “we want you to stay” but new research shows that more than one million foreign workers are considering leaving, prompting fears of a Brexit brain-drain.

The survey by accountancy giant Deloitte showed 36 per cent of non-British workers currently in the country said they were thinking about leaving by 2022 with 26 per cent planning to move even sooner, by 2020.

This figure represents 1.2 million jobs out of 3.4m migrant workers in Britain, underscoring the severe jobs crisis facing the country as it begins the Brexit process.

According to the survey, highly-skilled workers from EU countries are the most likely to consider leaving with 47 per cent thinking about upping sticks in the next five years.

To change their minds and stay, 32 per cent of skilled foreign workers said they would need to hear more positive statements from the UK Government that they remained welcome.

Angus Knowles-Cutler, vice chairman at Deloitte, noted: "At times of uncertainty, skilled workers are quickest to get their CVs out. You can't necessarily expect all the best and brightest to wait around for another few years of uncertainty."

Setting out more details of the UK Government’s plan to protect the rights of EU nationals once Britain is out of the Brussels bloc, the Prime Minister said they would continue to be able to bring dependent family members to join them.

"No families will be split up,” declared Mrs May in a Commons statement. “Family dependants who join a qualifying EU citizen here before the UK's exit will be able to apply for settled status after five years.

"After the UK has left the European Union, EU citizens with settled status will be able to bring family members from overseas on the same terms as British nationals."

She also promised a "streamlined and light touch" system to enable EU nationals who have been resident in the UK for five years to apply for "settled status" giving them indefinite leave to remain.

"They will be treated as if they were UK citizens for healthcare, benefits and pensions," Mrs May told MPs, stressing how the “fair and serious offer” was being made on the basis that it would be fully reciprocated by the remaining 27 member states to the one million Britons living on the continent.

On Friday, the PM received a frosty response from some EU leaders in Brussels with Donald Tusk, the European Council President, saying the UK plan fell "below our expectations".

However, Mrs May insisted the reaction from individual leaders had been "very positive" and there had been a "strong sense of mutual goodwill" in trying to reach an agreement as soon as possible.

But Jeremy Corbyn said that by making her offer only after the negotiations had begun, the PM had dragged the issue of EU citizens’s status into the complex and delicate trade negotiations with the EU.

"This isn't a generous offer. This is confirmation the Government is prepared to use people as bargaining chips," declared the Labour leader.

Ian Blackford, the SNP leader, said it was “shocking” to hear how David Cameron had supposedly pledged to guarantee unilaterally the rights of EU citizens but that Mrs May as the then home secretary had blocked the move.

“Does the Prime Minister accept she was wrong, and will she now do the right and honourable thing and reassure thousands of concerned EU nationals living in the UK today by unilaterally guaranteeing their rights? We created these circumstances; we should be showing leadership,” insisted the Highland MP.

But the PM again insisted, regards the claim about her blocking her predecessor’s plan, that this was “not my recollection”.

She noted: “During the Scottish independence referendum the First Minister told EU nationals that, if an independent Scotland were not allowed to rejoin the EU, ‘they would lose the right to stay here’. We are not saying that to EU nationals here in the United Kingdom. We are saying: ‘We want you to stay and this paper is the basis on which we will ensure that you can stay and nobody will be forced to leave.’”

Meanwhile in Brussels, doubts continued to be raised about the May Plan.

Michel Barnier, the EU’s chief negotiator, said Brussels' goal was for citizens to enjoy the same level of protection as under EU law and that the UK proposals fell short.

"More ambition, clarity and guarantees is needed than in today's UK position," he insisted.