I recently chaired a cross-party tripartite meeting for MPs, MEPs and Lords at which I was asked to outline the likely negotiation process for Brexit after Article 50 is triggered. Here is summary of my presentation.

Once the UK has notified its intention to withdraw from the EU under Art 50 TEU, and presumably outlined its ideas as to what conditions, transitions and aspirations it desires for the future, the European Council (heads of state or government) will meet without the UK to determine its position in response, and to set the mandate for the Commission to negotiate with Britain on behalf of the 27. This may itself require some time, especially if the 27 have divergent views (and also if notification is given, as per the current intention of the UK government, just before the French elections and Easter), though probably not as long as it is taking the UK to formulate its position.

The 27 will not give the Commission huge leeway. They will continue throughout the negotiations to steer the objectives, the responses to British proposals, and the acceptance or rejection of possible compromises.

The Commission’s chief negotiator will be former Commissioner (and former French foreign minister, and former MEP) Michel Barnier. He will be able to draw on the technical expertise of Commission departments. The Commission will report back to the 27 who will discuss matters at several levels:

– at most (if not all) European Council (“summit”) meetings, for key, strategic decisions

– at meetings of the ordinary Council of ministers when it meets in its “General Affairs” format (generally European Affairs ministers)

– at meetings of COREPER (the Permanent Representatives – Ambassadors – of the Member States), where the detailed work will be done (COREPER is likely to be assisted by a dedicated working group)

– at the level of “sherpas”, the senior official from each country handling this issue (who for some countries could also be the Ambassador), in preparation of European Councils

The Council has set up a Task Force in its secretariat headed by Didier Seeuws (the former chief of staff to Herman Van Rompuy, the previous President of the European Council).

Any Art 50 agreement requires the approval of a qualified majority of Member States (20 out of 27, together representing 65% of the population of the Union) and the consent of the European Parliament. In practice the Member States will likely seek to agree the deal by consensus, but formally speaking only the European Parliament has a veto on the deal from the European side.

The European Parliament has appointed Guy Verhofstadt (leader of the Liberals in the EP and former Belgian PM) to be its representative at the negotiations. He will be invited to attend Sherpa meetings and will be briefed after meetings at all other levels. He will not be a signatory to any deal, but can speak knowing that he will be listened to, given the EP’s ultimate power to approve or reject the deal.

Mr Verhofstadt will report back in the EP to:

– the Conference of Presidents (the President of Parliament and the leaders of all its political groups) on the general developments

– the Conference of Committee Chairs (of the 20 parliamentary committees) on the detail in various policy areas. Committees are all currently drawing up documents on the issues that arise in their field.

Both currently include British MEPs (two Group leaders Kamal and Farage in the CoP and three committee chairs Moraes, McAvan and Ford in the CCC) and this is likely to continue to be the case after the January mid-term elections to such posts.

Parliament’s Constitutional Committee, of which Mr Verhofstadt is a member, will take an overview of the process and will be responsible for the committee stage of the European Parliament’s final evaluation of the deal. It has two British members, of which I am one.

If the final vote in the European Parliament is in the Spring of 2019, it will be just ahead of the European elections of that year.

In terms of attitudes of other MEPs, the initial reaction of expecting us to disappear quickly has been attenuated by a realisation that Brexit is the mother of all divorce cases and will take time – even just making the inventory of all the issues to be addressed, let alone having a position on them, is proving to be a mammoth task. Meanwhile, British MEPs are still full members until the day Britain leaves. Irritation is directed more at the UK government with its seemingly conflicting messages.

Colleagues from other countries often ask whether Brexit will inevitably go ahead, given that the referendum was advisory, that it was won by a narrow majority (they all heard Nigel Farage say before the referendum that 52-48 would settle nothing), with a questionable franchise (many have received letters from Brits living abroad in their constituencies who were unable to vote) and on the basis of many inaccurate claims (not to say lies) about the EU that they all heard.

To this, they get a variety of responses.

But if Britain were indeed to have a change of heart, the prevailing view here is that a notification under Art 50 can indeed be withdrawn – unless it were done simply to set the clock ticking again on the 2-year negotiating period by re-submitting it again the following week.

A particular interest for the European Parliament is whether Britain will leave before the 2019 European elections.

The date of departure is set by the Article 50 “divorce” deal and could be 2019 or later, after a transition period. Even if it were 2019, there are arguments for it to be the end of the year to avoid problems with items set on an annual basis like fishing quotas or budget contributions and payments. However, it would be odd to elect British MEPs if they were to serve for only 6 months. In that situation, the Article 50 agreement could provide for British MEPs to be elected by the national parliament from among its own members (serving a dual mandate) for this transitional period. This is what happens when a new country joins the EU, and exit could be considered to be the opposite of accession.

I hope that gives you an overview of how things look at the moment, with all due caveats that there are no precedents for any of this and we live in politically volatile times.