Last week’s Brexit select committee visit to Brussels served as a reality check. Europe is planning for life post-Brexit while the UK is stuck in an unreality of its own making. From the EU, the message came through strongly: no one wants no deal, but it could happen. Two weeks ago, in his evidence to the committee, David Davis admitted that if a deal isn’t done until March 2019, the vote of the UK parliament could come after Brexit day. This is counter to the expectations of parliament and has significant constitutional implications.

Davis’s admission led to a flurry of parliamentary activity with questions to the prime minister, points of order, amendments tabled and renewed support to enshrine a vote in statute. It has defined a new fault line in parliament – with desire for clarity about what the vote is, when it will come and anxiety about the balance of power between the executive and legislature. With the ever greater risk of a change in prime minister or even the government before March 2019, clarity about parliament’s role is even more urgent. And any prime minister will be stronger with a vote of parliament behind her or him.

What was also evident from Davis’s evidence to our select committee was that there is no road map if there is no deal. That’s why, after discussions with EU policy experts, I have tabled an amendment to the EU withdrawal bill both to define a road map and a vote of parliament on how we move forward.

It specifies the steps the government must take in the event of no withdrawal agreement or of a withdrawal agreement not being approved by parliament by 28 February 2019. Under article 50, if a member state decides to withdraw, the European council then provides guidelines for its negotiations with that member state. These guidelines were published on 29 April 2017 – just as MPs were leaving Westminster. The withdrawal agreement will need the consent of the European parliament before conclusion by the council. The vote of the UK parliament is a matter for us alone.

While we lost time with the snap election, the EU moved to organise itself for the negotiations. The European Parliament engaged MEPs early on to help develop unity for any negotiated withdrawal agreement. It set up a Brexit steering group, involving the majority of MEPs working under the aegis of the conference of presidents, to co-ordinate the parliament’s deliberations and resolutions on the UK’s withdrawal. They take evidence and meet Michel Barnier and key stakeholders before and after negotiations. The domino effect of Brexit has not materialised; instead commitment to the European Union despite its challenges has become more steadfast.

Barnier is going to follow the guidelines of the European council to the letter. That’s his mandate. Any room for manoeuvre on his red lines could well be through the process the European parliament is undertaking. It’s clear from our visit to Brussels last week that no one wants no deal, but if that is what happens, it’s going to hit the UK the hardest. Leading MEPs were more pragmatic about the ability of the EU to respond in a crisis if we run up to the wire, for example, on the terms of transition. They are less likely to want an extension of article 50. With European parliament elections in June 2019 and parliament likely to dissolve around April 2019, they want withdrawal matters largely concluded by the current EU parliament.

There were warning signs for greater challenges ahead. The unity around any withdrawal agreement may not be so straightforward to hold when the new parliament tackles the future trade deal. And the direct message from one well-informed MEP: if you want to leave the customs union you must then also accept the possible consequences for Ireland and the future of the Good Friday agreement. There will be a limit to how much the UK can have its cake and eat it.

The lack of vision in terms of our “end state” is part of the vacuum. It’s easy to knock something down that you don’t like but it’s far better done when you know what you are building in its place. The government should be working now to seek reform to freedom of movement rules and for us to stay in a reformed single market and the customs union. Citizen associate membership, as advocated by Conservative MP Jeremy Lefroy, has real merits and cross-party interest in limited jurisdiction of the ECJ on matters of trade and regulation could be part of how we square the circle.

May’s weakness in Europe stems much from her failure to engage parliament and the country in the process of Brexit – a stark contrast to the way in which negotiations and discussion are moving forward in the EU.

Enshrining the vote of the UK parliament in statute is a first and vital step. The farce of the sectoral analyses and the impression it leaves of a government hiding from transparency and scrutiny is damaging the government and affecting the work of parliament. May’s big test is whether she can rise above her own party’s politics and show she can lead the nation in navigating the big changes ahead.

Seema Malhotra is Labour MP for Feltham and Heston