Domestic economists and media outlets criticised Prime Minister
Rishi Sunak's assertion that CPTPP "demonstrates the real economic benefits of our post-Brexit freedoms", citing the
International Agreements Committee report that states that the percentage increase in the
United Kingdom's GDP provided by CPTPP membership is only 0.08%. Economist Sam Lowe also pointed out that this figure is low due to the UK already having bilateral free trade agreements with all member states, with the exceptions of
Brunei and
Malaysia. In a report released with the
2023 Autumn statement, the
Office for Budget Responsibility calculated that Britain's economy would gain just 0.04% to GDP in the "long run", which it defined as after 15 years of membership. Trade expert David Henig stated that benefits from Britain's accession to the trade bloc impact had been "hugely overhyped", adding that "some companies will benefit, but the effects will be very small". Business and Trade Committee chair
Liam Byrne criticised the Government for "dodging" scrutiny of the UK's accession to CPTPP, demanding
MPs should have had more time to debate the treaty. In contrast, the
Centre for European Reform estimated that the costs of leaving the European Union have reduced the UK's GDP by 5.5%, provoking criticism from prominent media outlets as to the extent of the benefits of CPTPP, particularly as an alternative to the
European Economic Area. However, due to the high growth of the UK economy in comparison to
Germany between 2016 and 2022, these estimates have been repudiated by Brexit advocates. In March 2024, the
Office for Budget Responsibility (OBR) reported that the UK is "broadly on track" to show a 4% reduction in the UK economy's potential productivity, as well as a 15% fall in trade compared to if the UK had stayed within the EU, maintaining its estimation despite facing criticism from Brexit supporters as being overly pessimistic; the OBR noted that growth in UK goods trade is well below other advanced economies and 10% down on 2019 levels at the end of 2023. The
National Institute of Economic and Social Research estimated that the negative impact of Brexit gradually escalates, reaching some 5-6 per cent of GDP or about £2,300 per capita by 2035. Trade Journalist Alan Beattie states that the 5 per cent of GDP long-run cost of leaving the EU single market and customs union is not compensated by trade agreements such as CPTPP, regardless of who joins it in the future, pointing out that the long run collective gain of CPTPP, the
Australia, and
New Zealand deals are worth just 0.2 per cent to UK GDP. Beattie argues that CPTPP, and any future trade agreement, that create obstacles to realigning with the
European single market are harmful to the
economy of the United Kingdom in the long term. Environmental campaigners criticised the UK government for agreeing to eliminate all import
tariffs on
palm oil from
Malaysia, a product blamed for widespread
deforestation, prompting outrage from
green campaigners. The British government's decision violates the United Kingdom's
COP27 pledge to end deforestation by 2030, which it had committed to less than a year prior in
Glasgow. Further concerns were raised by trade unions over clauses in the deal that will allow large companies to sue the UK government behind closed doors if they believe their profits have suffered from changes to
laws or regulations. The
TUC's general secretary,
Paul Nowak, noted that these clauses could allow large companies to sue on grounds such as an increase in the
minimum wage or bringing
energy companies back into
public ownership. In March 2023, British
Secretary of State for Business and Trade Kemi Badenoch argued Britain's decision to join the CPTPP gives it a strengthened presence and influence in the Asia-Pacific region which is rapidly growing in significance both
economically and
politically. Additionally, Badenoch also claimed the deal is the most significant
commercial agreement signed by the UK since Brexit, with a potential to grow in importance as the rise of Pacific Rim countries continues, with applications from
China and
Taiwan highlighting further market opportunities that Britain could gain access to through CPTPP. == Member state relations ==