Britain and the European Union have said they will intensify negotiations on reaching a comprehensive agreement on the terms of their future relationship.
Below are the four main areas where negotiators still have to overcome differences before a Brexit transition period, which began when Britain quit the bloc, runs out at the end of this year.
LEVEL PLAYING FIELD FOR COMPANIES
Though Britain left the EU on Jan. 31, the main terms of its membership will remain in place until the end of the transition period. But from the start of next year, it will no longer be bound by the EU's rules on state aid for companies and the bloc's environmental or labour standards.
If Britain allows these standards to deteriorate or does not keep up with evolving EU rules, British companies selling to the bloc will have what EU officials see as an unfair competitive advantage over their EU rivals bound by the costly regulations.
If British firms are to have easy access to the bloc's market, the EU says Britain must commit to sticking to similar standards as the EU has.
Britain wants to catch fish in its waters and sell them to the EU, a market of 450 million people. But EU fisherman also want access to British waters and want to know in advance how much fish they can catch to help plan their business. The trade-off between access to the EU market for British fishermen and access to Britain's waters by EU fisherman is at the heart of the dispute.
British police want access to various EU databases that contain sensitive personal records, such as DNA, and the EU wants to have legal guarantees that the data will be treated with the confidentiality required by EU law.
The EU wants Britain to observe the European Convention on Human Rights (ECHR), an international agreement to protect human rights and political freedoms in Europe which allows any person who feels their rights have been violated to sue a government in the European Court of Human Rights.
The EU and Britain have to find a way to settle mutual disputes in the future. While some form of international arbitration could be established, the EU can accept only its own top court -- the Court of Justice of the European Union -- as the institution that interprets EU law. Britain does not want EU courts ruling in disputes it may have with the bloc.