The key benefit is greater access to each other’s markets, and a commitment to eliminate or reduce 95% of import charges or tariffs.
But some are kept to protect sensitive domestic areas, such as Japan’s rice farming industry.
In addition, manufacturers who source ingredients from many different places can claim that their products qualify for preferential treatment.
This means they can tick the so-called “principle of origin” box, as long as 70% of the ingredients come from one of the participating countries.
These provisions could help UK manufacturers of goods such as machinery and medicines – our most valuable exports to these countries – by reducing their costs and allowing them to expand their supply chains in component countries.
Outside of trade, membership means that investors from CPTPP countries are treated the same as domestic firms when they invest in projects in other member states, leaving the UK Firms may benefit.
In 2017, CPTPP countries accounted for around £1 in every £12 of foreign investment in the UK, and so the other way around – supporting businesses and jobs.
In turn, countries must cooperate on regulations, such as food standards.
However, unlike the EU, the CPTPP is neither a single market nor a customs union.
So countries do not need to have the same regulations and standards.
And countries can make their own trade deals with others, as the UK does with the EU – although membership of the CPTPP itself is incompatible with rejoining the EU.