Henry Newman is Director of Open Europe.

As Conservative Home readers will know, I’ve been a reluctant supporter of Theresa May’s Brexit deal. Although I’ve thought there were substantive issues with the backstop, which required addressing, I also argued that the deal overall offered the safest path out of the EU, particularly given the Parliamentary maths and errors made during the negotiations. In my view some critics of the deal misrepresent it, while ignoring its various benefits, and can be unrealistic about the alternatives on offer at this stage.

Last week, MPs conclusively demonstrated they would support a version of the deal, if problems with the backstop could be resolved. But how possible is it to resolve those issues, and what can be achieved when?

European leaders are understandably irritated that Theresa May is seeking changes to a package she herself signed off in December. However, the Prime Minister has little choice – the deal suffered the biggest defeat in Parliamentary history. Getting it through the Commons will require movement. And it’s not unprecedented for the EU to revisit a negotiated deal. Back in 2009, Ireland had to get the EU to agree an additional legally-binding protocol to the Lisbon Treaty, long after European leaders had signed things off in December 2007.

But there’s now a structural problem. As Open Europe’s man in Brussels, Pieter Cleppe, revealed, Brexit is now being handled by Martin Selmayr, the Commission’s Secretary General. Changes will now need sign off by all EU leaders – rather than Michel Barnier – and the next scheduled meeting of the European Council isn’t until late March. However, the BBC’s eagle-eyed Adam Fleming spotted a meeting of the Council, with the Arab League, in Sharm el-Sheikh in late February. Might that provide a moment to approve any changes?

What’s the mood of the EU? My understanding is that most members are open to helping the UK, but Ireland is resisting. Germany wants clarity on what changes would deliver a Commons majority for a deal although sources are ruling out a move in the next fortnight. Perhaps unsurprisingly, France is yet again emerging as a major roadblock. There’s also been a change of views on Article 50 extension. The EU wants to avoid looking ‘responsible’ for No Deal, so is unlikely to refuse a request for delay (although it may come with conditions). However, Paris is now leaning towards backing a long extension – for up to 21 months.

What can be achieved? Officials warn the ‘Malthouse Compromise’ is a non-starter with the EU, which is unsurprising given that it is premised either on the wholesale replacement of the backstop or a sort of managed No Deal. Kit Malthouse achieved the seemingly impossible by brokering something to which Nicky Morgan and Steve Baker could both sign up. He did a great service to Party unity, but the problem is getting Brussels to agree. What’s more possible is a legally-binding protocol, that sits alongside the Withdrawal Treaty.

What should it say? It needs to do two key things: first, provide clarity on exiting the backstop, and second, reassure the DUP and others that Stormont will have a “lock” over any new regulatory divergence if the UK enters the backstop. The Government has already committed to this, but putting it into international law would provide additional assurance.

Getting clarity on exiting the backstop won’t be easy. But May will need to propose a menu of options (helpfully, Open Europe will publish a briefing later today setting ideas out). When Geoffrey Cox, Steve Barclay and David Lidington sit down with EU leaders they can’t risk appearing ‘nebulous’.

If the EU won’t bite on Malthouse, what about a sunset clause combined with objective criteria that any “alternative arrangements” must achieve? As Professor Verdirame and I argued previously, the UK should also reserve its rights under the Vienna Convention if the EU fails to use “best endeavours” to agree a replacement deal. That doesn’t provide the unilateral rip cord that some seek, but it would mean that Britain had an arguable legal case if the EU sought to ‘trap’ us in the backstop.

Some critics claim that a time limit defeats the point of a backstop. But given that the EU itself argues that Article 50 cannot create a permanent relationship, surely an expiration date of ten years from the end of Article 50 would be reasonable? That would mirror the GATT treaty (Article XXIV) which allows for interim trade agreements of up to ten years. The EU would be loath to accept a limit, but some in Government believe that by that point the backstop would be legally challengeable anyway (ironically at the European Court).

In the Sun on Sunday, Jacob Rees-Mogg, the ERG’s chair, seemed to further soften his Brexit position (he previously argued that although he prefers No Deal to the Prime Minister’s deal, he prefers her deal to Remain). He wrote he has “come to the conclusion that leaving on March 29 is at risk”. This is important. There’s a strong chance that when the Brexit deal is next put to Parliament on 14th February, MPs could back a version of the Cooper amendment, seeking to seize control of the Brexit timetable and delay the exit date. This would be very unfortunate – it would reduce pressure on the EU to compromise on the backstop. Countries like Germany are waiting to see what happens on Valentine’s Day before moving on the backstop.

However, it’s becoming increasingly likely that the Government will – as the Foreign Secretary suggested last week – need a technical extension of Article 50 to complete ratification of the Brexit deal. Perhaps the Prime Minister should announce that she would be open to a short extension, but only once Parliament backs an actual deal. I think this should be acceptable to Eurosceptics. For example, the influential John Whittingdale said yesterday he was “willing to consider” an extension “only for the specific period required to get a bill through Parliament which would legislate for the Withdrawal Agreement”. It could also dissuade some wavering MPs from backing the Cooper amendment.

Finding a possible ‘landing zone’ for a Brexit compromise with the EU will be challenging but some sort of legally-binding protocol improving the backstop should be possible, especially if Cooper is defeated. It remains unclear though, how many of the Conservative critics of the Prime Minister’s deal are looking for ladders to climb down, rather than crosses on which to martyr themselves. But ultimately, as Rees-Mogg went on to warn this Sunday in a curious echo of the Prime Minster own words, there is now a risk not just of Brexit being delayed but “even [of] no Brexit at all.” MPs should push for the backstop’s issues to be addressed, but insisting that it’s the ‘Malthouse compromise’ or nothing is a risky path.