It provisionally applied[3][4] from 1 January 2021, when the Brexit transition period ended,[5] before formally entering into force on 1 May 2021, after the ratification processes on both sides were completed: the UK Parliament ratified on 30 December 2020;[6] the European Parliament and the Council of the European Union ratified in late April 2021.

[7] It provides for free trade in goods and limited mutual market access in services, as well as for cooperation mechanisms in a range of policy areas, transitional provisions about EU access to UK fisheries, and UK participation in some EU programmes.

Compared to the UK's previous status as an EU member state, on 1 January 2021 the following ended as they are not incorporated in the TCA or the Brexit withdrawal agreement: free movement of persons between the parties; UK membership in the European Single Market and Customs Union; UK participation in most EU programmes; part of EU–UK law enforcement and security cooperation such as the access to real time crime data; defense and foreign policy cooperation; and the authority of the European Court of Justice in dispute settlement (except with respect to the Northern Ireland Protocol[8]).

In addition, two other separate treaties were negotiated, signed, and ratified in parallel around the same time by the UK and the EU/Euratom: an agreement on exchange of classified information[9] and another on cooperation in the field of nuclear energy.

[11] Since then, the UK contributed to making and was subject to EU law, whose application was governed by the European Court of Justice.

[14] The trade agreement, negotiated under increasing time pressure due to the end of the transition period on 31 December 2020, had to address all of these issues.

[19] As the TCA was not treated as a mixed agreement, no national ratification procedures were needed in the member states.

[26] On 27 April, the European Parliament gave its consent to the agreement after a plenary vote (660 in favour, 5 against, 32 abstentions).

[2] Agreement on the draft text of the TCA was only reached in late December 2020, while the parties planned provisional application on 1 January 2021.

The parties therefore signed the draft text, of which the articles had not been continuously numbered and which was subject to legal revision before it could enter into force.

[37] There are rules to facilitate the cross-border provision of services in certain fields, such as digital services (including as regards data protection rules), public procurement (extending the coverage of the WTO GPA somewhat[38]), business trips and secondments of highly qualified employees.

[37] With respect to energy, there is to be regulatory and technical cooperation,[38] as well as a reconfirmation of the Paris Agreement climate goals.

[37] The UK has concluded a separate agreement with Euratom on peaceful cooperation on nuclear technology,[40] which has not entered into force.

[38] Certain existing intellectual property provisions exceeding TRIPS commitments (including a 70-year copyright term) are to be preserved in the EU and the UK.

[38][37] During a transitional period of 5+1⁄2 years, EU fishing quotas in UK waters will gradually be reduced to 75% of their pre-Brexit extent.

[38] The President of the European Commission, Ursula von der Leyen, called the TCA "a fair and balanced agreement" that would allow Europe "to leave Brexit behind us and look to the future.

[48] Prime Minister Boris Johnson said that the TCA would allow the UK "to take back control of our laws, borders, money, trade and fisheries" and would change the basis of the EU–UK relationship "from EU law to free trade and friendly cooperation".

[49] The Scottish National Party opposed the TCA because of the economic damage it said leaving the single market would inflict on Scotland.

[57][58][59] A YouGov survey of 29–30 December 2020 reported that 57% of respondents wanted the UK Parliament to accept the TCA and 9% to oppose it, with Conservative (78%) and Leave supporters (69%) more in favour than others.