Madrid: As with any set of negotiations, any final deal requires compromise and a flexible bottom line.

The European Commission and the other 27 European Union nations have agreed three core issues must be dealt with satisfactorily before Brexit negotiations begin on any other issues, and progress must be tangible by the time European leaders gather in Brussels on October 20.

The EU27’s three core issues

Citizen’s rights: The EU wants an agreement on the rights of the 2 million citizens from EU member states that currently reside in the UK. Similarly, it wants an agreement on the rights of the 1.2 million UK citizens who currently live in other EU member states.

700,000

Britons are living in Spain and Portugal alone.

Settling accounts: The EU wants the UK to agree on a sum to settle its accounts when it leaves the EU. Michel Barnier the EU’s chief negotiator, believes the amount should be €65 billion (Dh281 billion), while Boris Johnson, the UK’s Foreign Secretary, says the UK doesn’t owe a penny.

€20 billion

Reported offer by UK Prime Minister Theresa May

The Irish border: The EU wants to ensure that the border between the Republic of Ireland and Northern Ireland remains open and without frontier or customs checks. Any return to a frontier with security or tax would impede the peace process underway in the British-ruled province, and there must be free movement of goods and services between north and south.

€3.4 billion

Amount in trade across the Irish border in 2015

The UK’s core points

UK Prime Minister Theresa May laid out the UK’s negotiating position in a letter to the European Council that triggered Article 50 of the Lisbon Treaty on March 28. Then, there were 12 main points:

Providing certainty and clarity: The UK promised that where ever it could, it would provide certainty in the negotiations.

Taking control of laws: The UK wants to ensure than any final deal will end the European Court of Justice’s authority over its national laws.

Strengthen the union: The UK says it wants to ensure any deals works for all parts of England, Scotland, Wales and Northern Ireland. It says it committed to the principles of the Good Friday Agreement that brought peace to Northern Ireland.

Protecting ties with Ireland: The May government says it is committed to finding a practical solution to the Irish border and maintain the open travel agreement between the two states. (Both states are outside the Schengen visa system that covers continental Europe).

Controlling immigration: The British government wants to control the number of EU nationals coming to the UK.

Security citizens’ rights: London wants to secure the status of EU citizens now living in the UK, and those of UK citizens living in the EU “as early as we can”.

Protecting workers’ rights: The UK pledges to protect and enhance the existing rights of workers.

Ensuring free trade: The UK wants to secure free trade with the rest of the EU in a new wide-reaching free trade deal, and a customs union as well.

Trade deal with other nations: The UK government says that as well as securing a new free trade with the EU, it wants to negotiate deals with other nations. (Under EU treaties, trade deals are an EU responsibility, and the UK cannot negotiate its own deals while still in the EU).

Science and innovation: The UK says it wants close collaboration with its European partners to ensure the UK remains at the “vanguard of science and innovation”.

Crime and terror: The UK says it will seek a “phased implementation” on new security and intelligence-sharing avenues to fight terror and “uphold justice across the EU”.

Delivering a smooth and orderly exit: The May government pledged that it would seek a phased process of implantation with the remaining member states to prepare “for new arrangements that will exist between us”.