The United Kingdom became the 12th member of the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, or CPTPP, as of Sunday.
The previous British government signed the accession treaty last year, with most members of the bloc having since ratified the UK's entry.
Officials hope membership could boost Britain's struggling economy by as much as $2.5 billion (roughly €2.4 billion) per year.
The country is trying to strike new trade deals abroad in the aftermath of leaving the European Union following its 2016 referendum on Brexit, with EU member states still accounting for over 40% of UK exports and more than 50% of imports.
What is the CPTPP?
The Comprehensive and Progressive Agreement for Trans-Pacific Partnership had 11 members before the UK: Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam.
The CPTPP was salvaged from the ashes of the planned Trans-Pacific Partnership (TPP) bloc — which was supposed to also include the US — after Washington withdrew soon after the 2016 election of Donald Trump.
It retained most of the provisions of that deal, and lowers trade barriers between member states on a variety of goods. However, the pact offers far less comprehensive free trade than the uninhibited movement of goods and services with EU member states.
The bloc is seen as something of an economic counterweight to China in the Pacific region, though China is also one of several applicants currently seeking membership. Combined, its members currently account for roughly 15% of global GDP and a population of around half a billion.
UK's Starmer in Berlin for talks to reset ties with Europe
Deal inked under previous Conservative government
The previous Conservative government signed Britain up in July 2023, with then Business and Trade Secretary Kemi Badenoch — now the leader of the opposition with Labour in power — calling it "the biggest trade deal" since the UK left the European Union.
Britain has secured a number of trade deals, including with Australia, New Zealand and Singapore since leaving the EU's single market at the start of 2021. Critics, however, contend that Brexit's economic impact dwarfs that of these deals.
Labour's Business Secretary Jonathan Reynolds said the country was "uniquely placed to take advantage of exciting new markets, while strengthening existing relationships."
"Today's news is further proof that the UK is a wonderful place to do business, with an open, outward-looking economy driving the growth people can feel in their communities," Reynolds said.
He said his government would in 2025 publish a trade strategy that "will finally put in place a long-term, strategic plan for international trade that helps businesses and consumers and, ultimately, grows the economy."
Badenoch, meanwhile, said it had been her party that delivered the deal bringing the UK somewhat closer to the "fastest-growing economies in the world."
"However, joining a trade bloc is only the start. Labour spent the last parliament mocking our CPTPP negotiations, and they now have a responsibility to ensure that UK companies can make the most of this landmark deal," she said.
msh/sri (AFP, dpa)