The British Union flag and the European Union flag are seen flying behind a clock in the City of London, Britain, January 16 , 2017. REUTERS/Toby Melville

LONDON (Reuters) - The British government should make a unilateral decision now to protect the post-Brexit rights of European Union nationals living in Britain, a committee of lawmakers said in a report published on Sunday.

Prime Minister Theresa May has said she wants the issue to be dealt with as a priority in upcoming Brexit negotiations but is not prepared to offer a guarantee until other EU states agree to a reciprocal deal for Britons living abroad.

“They did not have a vote in the referendum, but the result has left them living under a cloud of uncertainty,” Hilary Benn, an opposition Labour lawmaker and chair of the Exiting the EU Committee, said in a statement.

“They do not want to be used as bargaining chips. Although the government has said it wants EU citizens to be able to remain, this has not offered sufficient reassurance that the rights and status that they have enjoyed will be guaranteed. It should now do so.”

Parliament’s upper house inflicted a defeat on May this week, voting for a change to her Brexit plan that says she can only trigger formal divorce talks with the European Union if she promises to protect the rights of EU citizens living in Britain.

May is hoping to overturn that change when the legislation returns to the lower house of parliament.

The Exiting the EU committee, made up of lawmakers from all the main political parties, also said the current process by which EU nationals can apply for permanent residence was not fit for purpose and should be streamlined.

With an estimated 3 million EU nationals living in Britain, the government need to put extra resources in place to deal with the number of applications it could face, the committee said, adding that it should announce as soon as possible what the cut-off date would be for EU citizens arriving in Britain.

“We were told that at pre-referendum rates of processing, giving residence documents to all potentially eligible applicants using the current system would take the equivalent of 140 years,” said Benn.