Writing in The Guardian, he said that while Australia, Canada and New Zealand would “do whatever they could” to work out new free-trade agreements with the UK, their total population of 65 million people does not “come within a bull’s roar of Britain’s adjacent market of 450 million Europeans”.
Discussing the prospect of a free-trade agreement with Delhi, Mr Rudd wrote: “As for India, good luck! India’s trade and commerce bureaucracy is the most mercantilist and outright protectionist in the world.”
His article came as Theresa May rushed to Strasbourg on Monday to agree “legally binding” assurances with European Commission president Jean-Claude Juncker.
Ms May said the deal created an arbitration channel for any disputes on the Irish backstop, “entrenches in legally-binding form” existing commitments it will be temporary and binds the UK and EU to start work on replacing the backstop with other arrangements by December 2020.
But in a hammer blow to the Ms May’s chances of forcing her new deal through Parliament, the attorney general on Tuesday morning insisted the UK could still be trapped in the Irish backstop indefinitely.
Mr Rudd, who was prime minister between 2007 and 2010, and again briefly in 2013, cautioned a free-trade agreement with India was “the ultimate mirage constructed by the Brexiteers”.
He described it as being “as credible as the ad they plastered on the side of that big red bus about the £350m Britain was allegedly paying to Brussels each week. Not”.
The former prime minister also warned Brexit will weaken the EU on the international stage, at a time when Donald Trump’s US administration is becoming increasingly isolationist and the West faces growing assertiveness from Russia and China.
“The bottom line is that a European Union without Britain will be a weaker international actor than it has been, particularly if the European centre of political gravity increasingly moves in a more populist direction,” he wrote.
“Without a strong Europe, the continuing idea of ‘the West’ begins to look very weak indeed. And authoritarians around the world would like nothing more than a fully disembowelled West, no longer confident of what it actually stands for any more.”
Mr Rudd called on Britain to “use this critical fortnight to start turning all this around”.
“For Britain’s economic self-interest, as well as the wider political interests of the western community of nations, Britain should remain in the EU,” he said.
He urged Labour and Conservative Remainers to unite to delay Brexit beyond 29 March, and said they should then support a second referendum to offer Britain “a clear, informed choice between two tangible, concrete proposals: either voting for Theresa May’s deal, or for Britain to remain in the Union”.
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