Britain on Sunday became the first European nation to join a major Indo-Pacific trading bloc, in what has been hailed as the country's biggest trade deal since Brexit.

The UK is officially now the 12th member of the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP).

The UK formally signed the accession treaty last year.

Officials hope membership will boost Britain's flagging economy by as much as £2.0 billion ($2.5 billion) a year.

According to government figures, the value of UK total trade in the 12 months to the end of September was £1.7 trillion.

The alliance comprises fellow G7 members Canada and Japan, plus long-standing allies Australia and New Zealand, alongside Brunei, Chile, Malaysia, Mexico, Peru, Singapore and Vietnam.

Created in 2018, it has been seen as a bulwark against Chinese dominance in the region, although Beijing has applied to join.

The bloc, which accounts for about 15 percent of global gross domestic product (GDP), will give British businesses trade access to a market of more than 500 million people.

The previous Conservative government signed Britain up in July 2023, with then Business and Trade Secretary Kemi Badenoch calling it "the biggest trade deal" since the UK left the European Union.

Britain has secured a number of post-Brexit trade deals, including with Australia, New Zealand and Singapore since it left the EU's single market at the start of 2021.

It is also pursuing one with Gulf countries, and last month Labour Prime Minister Keir Starmer announced that Britain and India are to resume stalled talks to agree a free trade deal.

A much sought-after trade deal with the United States remains elusive and could become even less likely when Donald Trump enters the White House in January.

A deal with Canada has also failed to materialise.