European political leaders met in Brussels yesterday for the final summit of one of the most difficult ever years for the EU. The agenda had a significant Russian and Ukrainian theme and EU sanctions against Moscow were extended for a further six months, including curbs on access to international financing, and restrictions on defence and energy cooperation.

Correspondingly, the EU’s future relationship with Ukraine was also discussed following European Commission President Jean Claude Juncker’s announcement last month that the EU will grant Ukrainians visa-free travel across the continent by the end of 2016. While Brussels would now like to see stronger political, economic and trade ties — with Ukraine getting EU “associate status” — the Dutch Prime Minister Mark Rutte won a concession that this does not automatically confer military assistance from European countries in the future for Kiev, nor that it will necessarily accede to become a full member of the EU in the future.

These issues are key for Rutte, whose coalition government could lose power in March’s elections, since the Netherlands is still haunted by the MH17 disaster in which 196 Dutch citizens died when an aircraft was shot down over Ukraine. In April, the Dutch populace voted two-to-one, in a low-turnout referendum, that the government should not sign into law the EU-Ukraine treaty which has been ratified by the other 27 member states, and Rutte had threatened to scotch the deal unless he secured yesterday’s concessions.

On the 25th anniversary of the Maastricht deal, widely seen as one of the high moments of European integration, Brexit was also on yesterday’s agenda. Although UK Prime Minister Theresa May attended the summit, she was not invited to the evening discussions when the UK’s pending exit of the EU was the key topic of conversation.

With May having re-stated that she wants — before end-March — to trigger Article 50, the mechanism for formal exit negotiations to begin between the United Kingdom and the EU, yesterday’s discussion helped set the agenda for what could be a very important European summit meeting in Malta in February. The tone between the sides appears to have, recently, hardened and the European Commission’s chief Brexit negotiator Michel Barnier has indicated that any deal must now be done in 18 months, rather than two years, to leave enough time for the European Parliament, the United Kingdom, and the 27 EU member states to approve any settlement.

What experts have said about Brexit Show all 11 1 /11 What experts have said about Brexit What experts have said about Brexit Chancellor of the Exchequer Philip Hammond The Chancellor claims London can still be a world financial hub despite Brexit “One of Britain’s great strengths is the ability to offer and aggregate all of the services the global financial services industry needs” “This has not changed as a result of the EU referendum and I will do everything I can to ensure the City of London retains its position as the world’s leading international financial centre.” Reuters What experts have said about Brexit Yanis Varoufakis Greece's former finance minister compared the UK relations with the EU bloc with a well-known song by the Eagles: “You can check out any time you like, as the Hotel California song says, but you can't really leave. The proof is Theresa May has not even dared to trigger Article 50. It's like Harrison Ford going into Indiana Jones' castle and the path behind him fragmenting. You can get in, but getting out is not at all clear” Getty Images What experts have said about Brexit Michael O’Leary Ryanair boss says UK will be ‘screwed’ by EU in Brexit trade deals: “I have no faith in the politicians in London going on about how ‘the world will want to trade with us’. The world will want to screw you – that's what happens in trade talks,” he said. “They have no interest in giving the UK a deal on trade” Getty What experts have said about Brexit Tim Martin JD Wetherspoon's chairman has said claims that the UK would see serious economic consequences from a Brexit vote were "lurid" and wrong: “We were told it would be Armageddon from the OECD, from the IMF, David Cameron, the chancellor and President Obama who were predicting locusts in the fields and tidal waves in the North Sea" PA What experts have said about Brexit Mark Carney Governor of Bank of England is 'serene' about Bank of England's Brexit stance: “I am absolutely serene about the … judgments made both by the MPC and the FPC” Reuters What experts have said about Brexit Christine Lagarde IMF chief urges quick Brexit to reduce economic uncertainty: “We want to see clarity sooner rather than later because we think that a lack of clarity feeds uncertainty, which itself undermines investment appetites and decision making” Getty Images What experts have said about Brexit Inga Beale Lloyd’s chief executive says Brexit is a major issue: "Clearly the UK's referendum on its EU membership is a major issue for us to deal with and we are now focusing our attention on having in place the plans that will ensure Lloyd's continues trading across Europe” EPA What experts have said about Brexit Colm Kelleher President of US bank Morgan Stanley says City of London ‘will suffer’ as result of the EU referendum: “I do believe, and I said prior to the referendum, that the City of London will suffer as result of Brexit. The issue is how much” What experts have said about Brexit Richard Branson Virgin founder believes we've lost a THIRD of our value because of Brexit and cancelled a deal worth 3,000 jobs: We're not any worse than anybody else, but I suspect we've lost a third of our value which is dreadful for people in the workplace.' He continued: "We were about to do a very big deal, we cancelled that deal, that would have involved 3,000 jobs, and that’s happening all over the country" Getty Images What experts have said about Brexit Barack Obama US President believes Britain was wrong to vote to leave the EU: "It is absolutely true that I believed pre-Brexit vote and continue to believe post-Brexit vote that the world benefited enormously from the United Kingdom's participation in the EU. We are fully supportive of a process that is as little disruptive as possible so that people around the world can continue to benefit from economic growth" Getty Images What experts have said about Brexit Kristin Forbes American economist and an external member of the Monetary Policy Committee of the Bank of England argues that the economy had been “less stormy than many expected” following the shock referendum result: “For now…the economy is experiencing some chop, but no tsunami. The adverse winds could quickly pick up – and merit a stronger policy response. But recently they have shifted to a more favourable direction” Getty

As well as the UK exit deal, the EU is also mapping out how it best moves forward post-the UK’s referendum in the context of what could be another complex election year with national ballots in The Netherlands, France and Germany. This is a potentially divisive agenda for the remaining 27 states, but one area where there is consensus is enhancing security and border protection to emphasise the resilience and integrity of the continuing EU project.

EU security policy has come under intensified focus with recent terrorist atrocities on the continent; the ongoing migration crisis; and also Russia’s assertive posture; and Tusk has said that “people expect that the EU...will again be a guarantor of stability, security and protection”. Moreover, there is also an added political ‘window of opportunity’ to move forward on this agenda with High Representative of the EU for Foreign Affairs and Security Policy, Federica Mogherini, having launched in June a new global strategy on foreign and security policy, which helped trigger a discussion at yesterday’s summit about what Europe can potentially now do to aid citizens in and around Aleppo in Syria.

Several leading politicians have already called for a new, Twenty First Century European security pact. This highlights that a carefully crafted package of measures, including greater EU intelligence cooperation and strengthening Europe’s border force, could secure significant political traction, and, more controversially, the EU Commission also put forward a draft European Defence Action plan that proposes greater European military cooperation post-Brexit.

Beyond this, however, there is much more disagreement on the EU’s best way forward. Some senior decision-makers, including Juncker, favour a stronger integrationist response in select areas, but recognise the sensitivities of this, especially given the key upcoming 2017 national ballots.

Other policymakers, including Dutch Finance Minister Jeroen Dijsselbloem, the Chair of the Eurogroup of Finance Ministers, have argued for caution, asserting that if the “negative outcome of the UK referendum should be interpreted as a vote against Europe, it doesn’t make sense in my view to respond immediately by asking for more Europe” in the form of a new, potentially grand integration schemes. This Dutch scepticism of the wisdom of further integration is echoed in the French and German Governments given the significant potential for popular backlash against such moves ahead of the 2017 national elections there.

In Paris, for instance, there is concern that further controversial EU initiatives could provide a fillip to the far-right National Front’s Marine Le Pen. She is currently riding high in opinion polls and has promised a referendum on French membership of the EU if she is elected the country’s president in May.

Taken overall, EU political leaders are still scrambling to come to terms with the Brexit vote which will continue to set the political weather across the continent for months to come. Decisions taken in coming months, including on the security front, will define the longer-term political and economic character of the EU in the face of the divisions still remaining about how best to respond to what could be the union’s most significant ever setback.