Canada Ratifies the United Kingdom’s Accession to the CPTPP: Implications for Trade and Investment

On May 6, 2026, the Act to implement the Protocol on the Accession of the United Kingdom of Great Britain and Northern Ireland to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (Act) received royal assent, ratifying the accession of the United Kingdom to the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP). The Act is expected to enter into force by order of the Governor in Council shortly.

In addition to preferential tariff rates on customs duties for goods, the U.K.’s accession to the CPTPP will have significant implications for U.K. investors in Canada and Canadian businesses with direct and indirect investments in the U.K., including enforceable investment protections and access to investor-state dispute settlement (ISDS) arbitration mechanisms.

Background

The CPTPP is a comprehensive trade and investment agreement between Canada and ten other economies: Australia, Brunei, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam.

On December 15, 2024, the U.K. became the twelfth member of the CPTPP and the first country to accede to the agreement since its entry into force in 2018.

Prior to its accession to the CPTPP, the U.K.’s trade relationship with Canada was governed by the Canada-European Union Comprehensive Economic and Trade Agreement (CETA), portions of which are provisionally in force. Following the U.K.’s departure from the European Union, Canada and the U.K. entered into the Canada-U.K. Trade Continuity Agreement (TCA) as an interim bridge, preserving continuity of certain trade provisions while longer-term arrangements were negotiated.

The Act ratifies the accession of the U.K. to the CPTPP in Canadian law, giving full effect to the provisions of the CPTPP between Canada and the U.K. and significantly expanding the protections available to Canadian and U.K. investors.

Overview of the CPTPP

With the addition of the U.K., the CPTPP will form a free trade area representing more than 580-million consumers and over 15% of global GDP, expanding the agreement’s economic footprint.

The CPTPP provides a broad framework governing virtually all aspects of international trade, including trade in goods and services, investment, electronic commerce, labour mobility, government procurement, intellectual property and ISDS.

The Act provides for staged tariff reductions on a broad array of goods and adds the U.K., the Channel Islands and the Isle of Man to Canada’s list of countries with preferential tariff treatments under the Customs Tariff, resulting in duty-free importations within several years.

Key Benefits for Canadian Businesses

The CPTPP provides a range of benefits for Canadian businesses, including:

• Substantive investment protections: The CPTPP guarantees investment protections to U.K. investors in Canada and Canadian investors in the U.K. These include national treatment, most-favoured-nation treatment, fair and equitable treatment, and protection against expropriation without compensation.
• Access to ISDS: Chapter 9 of the CPTPP establishes a framework for ISDS, allowing Canadian investors in the U.K. and U.K. investors in Canada to bring binding investor-state arbitration claims before an independent arbitral tribunal against the host state when the state breaches the CPTPP’s investment protections.
• Broad sectoral coverage: The CPTPP creates new opportunities across a wide range of sectors, including agriculture, fish and seafood, forestry, industrial manufacturing, aerospace, information and communications technologies, metals and minerals, and environmental, financial and professional services.
• Transparent and predictable rules: The CPTPP establishes harmonized obligations relating to customs procedures, technical barriers to trade, and regulatory transparency and cooperation, reducing transaction costs for crossborder trade and investment.
• Cumulation of origin for preferential tariff rates: The CPTPP’s rules of origin allow inputs from any CPTPP member territory to count toward originating status for duty-free imports, offering more flexible supply chain options than the bilateral TCA rules.

Canadian and U.K. businesses with investments or commercial activities in either country should consider how the extension of CPTPP investment protections and trade provisions may benefit them.

For more information, please contact the authors or any other member of our International Trade or Investment Treaty Arbitration groups.