Below are key issues in the mandate, to be addressed during talks before Dec. 31, when Britain's transition period ends.
Rather than dozens of separate treaties dealing with various aspects of the relation between the 27 countries remaining in the European Union and Britain, the EU wants a single, overarching agreement that would cover these areas:
* Basic values and principles, ways in which the deal would be enforced, how disputes would be settled and how the agreement can be expanded if needed.
The future relationship deal should be periodically reviewed. If one side breaks essential elements of the deal, it could be suspended in part or whole.
There should be a governing body that would also facilitate dispute resolution and reach decisions by mutual consent. It could refer a dispute to an independent arbitration panel, whose decisions would be binding.
Where a dispute requires interpretation of EU law, it would only be done by the EU's top court.
If either side fail to implement the binding resolution, it could be fined or the agreement could be suspended.
* Provisions on trade and guarantees that British companies would not be allowed to undercut EU ones through lower labor or environmental or tax standards or thanks to government help - what the EU calls a level playing field.
The EU wants no tariffs or quotas in trade in goods, but also no dumping.
On financial services, a sector that produces around 7% of Britain's GDP, the EU will unilaterally decide whether to grant Britain "equivalence" status, which would acknowledge that the country's laws on financial institutions are equivalent to the EU's and therefore they can do business in the bloc.
The future deal should guarantee protection of intellectual property and patents, access to public procurement markets and facilitate digital trade.
The EU wants reciprocal visa-free travel, social security coordination, and rules for students and youth exchanges.
* The deal should include aviation to ensure that planes keep flying between Britain and the EU and that all EU airlines are treated equally and not discriminated against.
* There should be open-market access for road freight transport. But British truck operators should not be given the same rights for cabotage - moving goods between or within EU countries - as EU operators.
* In fisheries, an economically minor but politically sensitive issue, the EU wants continued reciprocal access to British waters and defined stable fishing quotas. The mandate says access to British waters for EU fishing fleets will determine the shape of the trade agreement in goods. The EU wants a deal on fisheries by July 1, 2020.
LEVEL PLAYING FIELD
* The EU wants to make sure Britain will not undercut EU companies by lowering labor, environmental, tax and state aid standards it was obliged to uphold as an EU member.
The EU wants therefore to be able to apply "autonomous interim measures" in case of unfair competition. It also wants Britain to apply EU state aid rules to companies that export to the EU to be enforced by an independent authority working closely with the European Commission.
* Under the future deal, Britain would have to apply tax standards applicable in the EU on exchange of information on income, financial accounts, tax rulings, country-by-country reports, beneficial ownership and potential cross-border tax planning arrangements.
* From 2021, Britain should not lower its existing labor and social protection standards and ensure effective enforcement of these laws.
* The same would apply to its environmental protection laws and its commitments to fighting climate change. Britain should also keep a system of selling permits for carbon emissions that would be linked to the EU Emissions Trading System (ETS).
* Law enforcement and judicial cooperation in criminal matters, as well as on foreign policy, security and defense.
Britain should respect EU personal data protection laws. Law enforcement and judicial cooperation in criminal matters could be automatically ended if Britain denounced the European Convention for Human Rights.
The deal should establish ways for Passenger Name Record reciprocal exchange, reciprocal access to DNA and fingerprints records as well as vehicle registration data.
The future agreement should establish cooperation between Britain and EU agencies for law enforcement and judicial cooperation - Europol and Eurojust.
Where Britain and the EU have mutual interests, the future deal should enable London to cooperate with the EU on foreign policy issues, in international bodies like the G7 and the G20 or to coordinate sanctions policy.
Britain and the EU should be able to share intelligence and jointly tackle irregular migration.
(Reporting by Jan Strupczewski; Editing by Hugh Lawson)
By Jan Strupczewski