The British Prime Minister's Brexit proposals would deny the UK the opportunity to join a new free trade agreement bringing together some of the world's fastest-growing economies, experts have warned.

The white paper setting out Theresa May’s plans for life after Brexit specifically states that the UK could "potentially seek accession" to the new Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP) "on terms consistent with the future relationship with the EU".

However experts are warning that Mrs May's decision to seek a free trade deal with the EU on agricultural and manufactured goods would make CPTPP membership unlikely.

The CPTPP was signed earlier this year, after US President Donald Trump pulled the plug on its TPP predecessor by withdrawing the US just days after entering office in 2017.

Its 11 members include Australia, Canada, Japan, Malaysia, Mexico and Singapore, with South Korea, Indonesia and Thailand among countries expected to join soon.

Eliminating tariffs and quotas between members and involving mutual recognition of regulations and rules on cross-border investment, it is seen as a swifter and more effective alternative to forging separate trade deals with individual member states.

In an essay for the Policy Exchange think tank, former Australian ambassador to the World Trade Organisation Geoff Raby warned that the Chequers deal would limit the UK's participation.

"By aligning UK policy to EU policy on agriculture and manufactured goods, the white paper will constrain the opportunities that the UK has to pursue an independent trade policy," said Mr Raby.

"Without being able to participate fully in the agricultural and manufactured goods dimension it is most unlikely that the UK would able to join, but if it did it would not be able to get the full benefits of the CPTPP."

Policy Exchange chairman Alexander Downer, the former Australian high commissioner to the UK, said Britain would be "a welcome addition" to the CPTPP, which would give it "unfettered access to many markets that represent a large part of the future of the world's economy".

But he warned that the ratification process has already seen tough negotiation to ensure that the Japanese agricultural sector was included in the agreement.

"The Chequers Agreement shows a desire for the UK to remain closely tied to the EU for manufactured and agricultural goods," said Mr Downer.

"In essence it says you want to be free to sell the things you're good at and protect less competitive areas of your economy.

"As the Policy Exchange paper highlights, the process of ratification has been difficult for some - Japan, for example, experienced heavy resistance from its agriculture sector.

"Having fought such battles to secure the comprehensive nature of CPTPP, it is unlikely that the UK will be accepted without meeting the same obligations."

The essay's co-author, Warwick Lightfoot, a former special adviser to chancellors Nigel Lawson, John Major and Norman Lamont, said: "Leaving the political relationship with the EU should not result in a more closed outlook on the world.

"Instead the UK should focus on the opportunities in the wider world if we adopt a more free trading approach which exposes our domestic market to greater competition and challenge."

A Department for International Trade spokesman said: "As set out in the white paper, the UK will pursue an ambitious bilateral trade agenda after leaving the European Union, taking full advantage of the flexibility its proposal for the future economic partnership provides.

"As we undertake further work to understand the opportunities CPTPP presents for UK consumers and businesses, we are seeking the views of members of the public, interested bodies and stakeholders.

"We also continue to engage with key partners internationally, to gain a better understanding of the process for applying for CPTPP membership."

Meanwhile, Mrs May is travelling to Austria for Brexit talks with Austrian Chancellor Sebastian Kurz and Czech prime minister Andrej Babis.

It is part of several meetings across Europe which the PM and her ministers are carrying out to win over support for the Chequers Brexit blueprint.

Mrs May was dealt a blow by Brussels yesterday as the EU’s chief Brexit negotiator, Michel Barnier, rejected the customs proposals that form a key plank of the plan.