Media playback is unsupported on your device Media caption Peter Lilley and Theresa May on rights of UK citizens living in EU nations after Brexit.

Britons living around Europe would have been left "high and dry" if the rights of EU citizens to stay in the UK had been guaranteed, the PM has said.

Theresa May said EU leaders' remarks showed it was "absolutely right" for the UK not to have acted unilaterally.

EU Council president Donald Tusk has said there can be no "reciprocal" deal on expats until formal talks begin.

He was responding to criticism from Tory politicians who accused EU figures of "standing in the way" of a deal.

Replying to a question in the Commons from Conservative MP Peter Lilley, Mrs May said she hoped the issue would be examined early during the Brexit negotiations, which cannot begin until she has triggered Article 50 of the Lisbon Treaty.

The PM said it was "right" to give reassurance to both sets of citizens, adding: "But I think the reaction that we've seen shows why it was absolutely right for us not to do what the Labour Party wanted us to do, which was simply to give away the guarantee to rights of EU citizens here in the UK, because as we've seen that would've left UK citizens in Europe high and dry."

The letter from 81 mostly Conservative MPs and peers called for a speedy resolution and pointed the finger at EU Brexit negotiators for holding up a deal.

Image copyright EPA Image caption European Council president Donald Tusk says Article 50 must come before any negotiations

It said members of the European Commission appeared "worryingly indifferent" for British and EU citizens and called for discussions to "move forward quickly".

"People are not bargaining chips," it said.

"Human beings are not cards to be traded 'tit for tat' in a political playground."

In response, Mr Tusk said their criticism had "nothing to do with reality".

He said the vote for Brexit - not the stance taken by EU negotiators - had created "anxiety and uncertainty", saying the best way to "dispel the fears and doubts of all the citizens concerned" was to trigger Article 50, which begins a two-year negotiation process.

The EU was ready to begin talks as soon as Article 50 was triggered, he said.

There have been calls from some MPs for the government to offer a unilateral guarantee to EU nationals in the UK, but ministers have said this must form part of a deal with other member states for Britons living overseas.

In the House of Lords, Home Office Minister Baroness Williams of Trafford quoted Mrs May's comment from PM's questions and said the "only circumstances" in which it would not be possible to protect the status of EU nationals in the UK would be if "British citizens' rights in the other EU member states were not protected in turn".

The government's stance was criticised by Lib Dem Baroness Ludford, who said there was cross-party support for a unilateral commitment from the government.

This would be the "morally right thing to do" she said, adding that the 27 other EU member states would then find it impossible not to match the UK's offer.