Britain's Prime Minister Theresa May arrives at Downing Street, in London,. (Jonathan Brady/PA via AP)
The EU has a message for British Prime Minister Theresa May as she plots a path out of the Brexit impasse: a back-up plan for the Irish border can be tweaked, but will have to be included in any divorce deal.

With less than nine weeks until the UK is due to leave the EU on March 29, there is no agreement yet in London on how, and even whether, to leave the world’s biggest trading bloc.

Parliament defeated May’s deal two weeks ago by a huge margin, with many Brexit-supporting rebels in her Conservative Party angry at the Irish backstop - an insurance policy aimed at preventing a hard border in Ireland if no other solutions can be agreed upon. The backstop is the most contentious part of May’s deal.

Ahead of today’s votes in the British parliament on a way forward, lawmakers in May’s party are pushing for her to demand the EU drop the backstop and replace it with something else.

Ireland said the backstop was staying and the European Commission repeated yesterday that the withdrawal agreement text, and its backstop component, is not open for renegotiation.

“The European Parliament will not ratify a withdrawal agreement that doesn’t have a backstop in it, it’s as simple as that,” Ireland’s Deputy Prime Minister Simon Coveney told the BBC.

As the Brexit crisis goes down to the line, however, EU officials indicated there might be wriggle room if May came back with a clear, and viable, request for changes that she - and the EU - believe will secure a final ratification.

The question for May is whether the EU can offer enough to get a variant of her defeated deal through the British parliament.

Possible amendments floated by EU officials range from further public assurances that the backstop would probably never be used - or only for a brief period - to amending the text which accompanies the treaty, and which lays out expectations for the trading relationship that will come in after the transition.

The EU has explicitly said that if Britain were to stay in a customs union indefinitely, as the opposition Labour Party favours, that could leave the backstop redundant.

One key element is maintaining a united front with the Irish government, which insists it needs the backstop without a time limit to ensure there is no physical frontier, which could become a target of the violence that has been reduced as a result of the two-decade-old Good Friday Agreement peace deal.

A looming no-deal Brexit, in which the EU insists Ireland cannot leave an open door to British goods, has highlighted the difficulty Ireland will face if the backstop issue scuppers an agreement.

EU leaders are open to giving May more time beyond March 29 if she can convince them she will use the time to secure the elusive orderly outcome, whether leaving or staying.

Brussels and the national governments are keeping their options open, however, determined not to give in to British demands that they believe would undermine their single market, but also anxious to avoid chaos.

“Theresa May must show us a majority for something concrete. Come back and be specific about what she needs to get the deal passed,” one EU source told Reuters.

May is trying to use a series of votes in parliament today to find a consensus that lawmakers in her own party could support, just two weeks since her deal suffered the biggest parliamentary defeat in modern British history.

In essence, May is forcing lawmakers to show their cards on what sort of Brexit, if any, they want. Reuters