The United Kingdom has signed a deal to join the Comprehensive and Progressive Agreement for Trans-Pacific Partnership, or CPTPP, a major Asia-Pacific trading bloc, becoming the first new member and first European nation to join since it was formed in 2018.

The UK's Business and Trade Secretary Kemi Badenoch formally signed the treaty confirming the UK's accession to CPTPP in New Zealand on Sunday, bringing barrier-free access for British businesses to a market of 500 million people a step closer.

With the UK's inclusion, the collective GDP of the bloc, comprising Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam, will amount to 12 trillion pounds ($15.7 trillion), or 15 percent of the global share, according to UK officials.

A government statement said that once ratified by Parliament and brought into force, the deal would mark the most significant trade agreement for Britain since its departure from the European Union in 2020, reducing tariff barriers for UK exporters to a consortium of countries, spanning 12 economies across Asia, the Pacific, and now Europe.

On signing the agreement, Badenoch said: "We are using our status as an independent trading nation to join an exciting, growing, forward-looking trade bloc, which will help grow the UK economy and build on the hundreds of thousands of jobs CPTPP-owned businesses already support up and down the country."

A proposed deal on the UK's membership was first reached in March after a two-year negotiation, and the formal signing cements the agreement before ratification.

Joining the trade group is expected to fuel more investment in the UK by CPTPP countries, valued at 182 billion pounds in 2021, said officials.

The move was welcomed by UK business figures on Sunday.

HSBC chief executive Ian Stuart said: "The UK's formal accession to the CPTPP marks a significant milestone for UK trade, enabling ambitious British businesses to connect with the world's most exciting growth markets for startups, innovation and technology."

Cath White, head of International at Belvoir Farm, said that the UK's accession to CPTPP will mean more than 99 percent of UK goods exported to CPTPP member countries will be eligible for zero tariffs.

"It will also ease administrative and commercial trade barriers to allow talented and passionate UK producers to tell their story on a worldwide scale," White said.

Institute of Export and International Trade Director General Marco Forgione told the PA Media news agency that some goods will become cheaper for UK consumers.

"From whisky to confectionery to cars to jewelry and clothing, the removal of tariffs will make our finest British products more readily available to consumers in the 'Indo-Pacific' bloc," Forgione said.

Some critics argue the impact of the deal will be minor, with government figures suggesting it will add just 1.8 billion pounds a year to the economy after 10 years, representing less than 1 percent of UK GDP, Sky News reported.

Last month, the opposition Labour Party's David Lammy accused ministers of "dishonestly" asserting that CPTPP membership would offset the loss of EU trade.