LONDON (Reuters) - British Prime Minister Theresa May accused her opponents in parliament of trying to "thwart" her agreement on Britain's exit from the European Union.

Before a crucial vote on the deal in the House of Commons next week, May said her opponents had not offered a credible alternative to her plan.

May rejected calls by pro-EU MPs to hold a second referendum on Britain's exit from the union, saying voters had made a "clear message" in 2016, when 52 percent chose to leave the EU.

"Many people who want to hold a second referendum want it in the hope that it will produce a different result," she said in remarks on the BBC's Today program. "That's not true."

"It's not about this deal, it's about trying to thwart the exit from the EU."

"It is important to work on the first vote," she said, and put the "national interest" in mind.

The British prime minister said that the members of parliament have three choices, just before the vote on her proposal for exit from the European Union: either agree on her proposal or face exit without agreement or even not to go out at all.

She said she was talking to MPs about giving parliament a bigger role in resolving the Northern Ireland arrangement, but gave no further details.

May has repeatedly refrained from answering questions about whether to postpone the vote, scheduled for Dec. 11, but has not hinted at possible concessions on the Northern Ireland arrangement.

On the other hand, said the Minister of exit from the European Union, Stephen Barclay, yesterday, that Britain will be ready to go out without an agreement in March, "but it takes a lot of work."

The European Court of Justice will issue a ruling on Monday to closely monitor whether Britain can rescind its decision to leave the European Union, a day before the British parliament voted on the EU exit agreement, the court said.