Taken from WIkipedia, so hold your own opinion on it;
The UK government has not produced an impact assessment that explains or quantifies the benefits it expects for the UK economy from accession to CPTPP. As such, it is a matter of dispute in UK as to whether accession is worth pursuing for economic reasons. Farmer, environmental and consumer groups have all raised concerns that the UK government will need to agree to lowering standards on pesticides, pig welfare and food labelling. These concerns have also been raised by the Scottish government.