British Prime Minister Theresa May's government said Tuesday it was aiming to agree a Brexit deal by July, making it likely that Britain's MEPs elected in next week's European elections will take their seats.

Ministers agreed at a cabinet meeting to continue talks with the main opposition Labour Party on how parliament might accept the divorce deal that May agreed with the EU last year, according to her spokesman.

But he said they also agreed it was "imperative" that any exit plan be approved before parliament's summer holiday, which normally begins at the end of July.

"What she (May) is working to do is to get a deal passed as soon as possible," he said.

Asked what this meant for Britain's 73 members of the European Parliament, the spokesman added: "The factual position is if MEPs are elected and (British) parliament has not approved a withdrawal agreement bill which has achieved royal assent by June 30, they will take their seats."

After twice delaying its exit from the European Union, Britain is reluctantly taking part in European Parliament elections on May 23, almost three years after the referendum vote for Brexit.

The government had hoped to get the London parliament's agreement for May's divorce deal in the coming weeks so British MEPs would never have to take their seats.

But if Britain is still a member of the EU when the new European Parliament convenes on July 2, they will have to be seated.

May opened talks with Labour six weeks ago after failing three times to get her agreement through the House of Commons in the face of objections from both her own side and the opposition.

But progress has been painfully slow and there are growing calls in May's Conservative party to abandon the talks.

Cabinet discussed on Tuesday what might happen if the talks fail, including a "Plan B" to hold a series of votes in parliament on possible Brexit options, May's spokesman said.