Britain's choice would be to leave the European Union without a deal or abandon Brexit altogether if its parliament rejects an agreement between the EU and Prime Minister Theresa May, European Council President Donald Tusk said today.
"A few days before the vote in the House of Commons, it is becoming more and more clear that this deal is the best possible - in fact, the only possible one," Mr Tusk said, ruling out any renegotiation by the EU if the British parliament votes down last Sunday's deal on 11 December.
"If this deal is rejected in the Commons, we are left with... an alternative: no deal or no Brexit at all. I want to reassure you that the EU is prepared for every scenario," he said during the G20 meeting in Argentina.
When asked about a Plan B for Brexit if her deal is defeated in parliament, Mrs May said at the summit: "I'm proposing my Brexit deal."
She said that the people voted for Brexit and "it is our job" to deliver it.
"The focus of myself and the government is on the vote that is taking place on 11 December. We will be explaining to members of parliament why we believe that this is a good deal for the UK," she said.
"I ask every member of parliament to think about delivering on the Brexit vote and doing it in a way that is in the national interest and doing it in a way that is in the interests of their constituents because it protects jobs and livelihoods."
Mr Tusk will chair an EU summit two days after the British parliament votes on the deal.
Britain is due to leave the EU on 29 March, although some campaigners hope the withdrawal can be stopped.
On Wednesday, the Bank of England warned Britain risked suffering an even bigger hit to its economy than during the global financial crisis ten years ago if it leaves the EU in the worst-case, no-deal Brexit scenario.
Asked in a BBC interview if she would seek a second vote,she declined to answer directly, repeating her comment that she was only focusing on the 11 December vote.