EU states could take revenge for Brexit by kicking out more than a million expats, a Brussels report has warned.

A leaked document drawn up by the European Parliament's legal affairs committee suggests countries may retaliate over tough immigration rules.

The warning comes amid a major row over reciprocal rights for EU citizens in the UK and Britons living on the continent.

Theresa May has complained that the club's leaders - including Angela Merkel - are blocking an immediate deal to reassure people they will not be displaced.

Theresa May - pictured in the Commons last week - has complained that EU leaders are blocking an immediate deal to reassure people they will not be displaced after Brexit

The PM has insisted that she wants to come to an arrangement as soon as possible after Article 50 is triggered next month.

But she has faced demands from Labour, the Lib Dems and some Tory backbenchers to offer a unilateral guarantee for more than three million European nationals.

The issue is set to be a key bone of contention when the Brexit Bill comes to the House of Lords later this month.

The leaked report, obtained by the Guardian, said it would be down to each member state to decide whether British citizens are allowed to stay after we formally quit the club in 2019.

'The fact that it appears to be particularly difficult for foreign nationals, even if married to UK nationals or born in the UK, to acquire permanent residence status or British nationality may colour member states' approach to this matter,' the document warns.

The document was drawn up by the European Parliament's committee on legal affairs this month, the newspaper said.

In a foreword to the report, Pavel Svoboda, the Czech chairman of the committee, writes: 'One important preliminary question affecting all policy areas is the extent to which transitional arrangements could be envisaged legally.

'It would seem to us that such arrangements could only be adopted by international agreement or a protocol to the treaties, which would require the unanimous agreement of the member states and ratification in accordance with their national constitutional tradition.

'It would seem difficult, if not impossible, to reach such an agreement before the end of the period provided for in Article 50.'

Jeremy Corbyn accused the Prime Minister of a 'Hunger Games approach to Brexit' by refusing to guarantee the rights of European Union citizens in the UK.

Jeremy Corbyn - pictured on the BBC last week - accused the PM of a 'Hunger Games approach to Brexit'

Mr Corbyn told the newspaper the report showed 'the human cost of a Tory-style Brexit'.

'Families, jobs and homes are all in the balance,' he said.

'There must be an end to this Hunger Games approach to Brexit negotiations, which gives no consideration to EU nationals in our country or British nationals living abroad.'

Lib Dem leader Tim Farron said: 'This issue could have been settled from the start if the Government had done the right thing and made clear EU citizens who have made the UK their home can remain indefinitely.

'Instead, millions of people on both sides of the channel are being left in limbo and faced with agonising uncertainty over their futures.

'Antagonising our European partners is no way to get a good deal for Britain and for the many UK citizens living in EU countries.'

A Home Office spokesman said: 'This Government has been clear, that we want to protect the status of EU nationals already living here and the only circumstances in which that wouldn't be possible is if British citizens' rights in European member states were not protected in return.

'The Prime Minister has reiterated the need for an agreement as soon as possible as part of the negotiations to leave the EU.'