British Labour leader Jeremy Corbyn has potentially canned any future trade deal with Australia, by saying he wants the UK to remain in the EU customs union.
The Opposition leader said on Monday if elected he'd seek a "new and comprehensive" UK-EU customs union to ensure tariff-free trade after Brexit.
The stance puts him at direct odds with Prime Minister Theresa May, who wants to be outside any customs union so Britain can sign free trade deals with countries around the world after leaving the EU.
Australia's is seeking a free trade deal with the UK as soon as Brexit is formalised.
Foreign Minister Julie Bishop made it clear during a visit to London earlier this month that a trade deal with the UK was reliant on leaving the customs union.
"Australia is very keen to pursue negotiations for a free trade agreement with the United Kingdom," Ms Bishop said during her visit.
"I think that would be precluded if the United Kingdom were to join the (EU) customs union, so our national interest, our priority, would be served by negotiating a free trade agreement with the United Kingdom."
Corbyn said Labour would demand the EU ensures the government "has a say in future trade deals" signed by the bloc, but appeared to admit the UK would not be able to sign its own agreements.
"We do not believe that deals with the US or China, would be likely to compensate for a significant loss of trade with our trading neighbours in the EU, and the Government's own leaked assessments show that," he said.
Foreign Secretary Boris Johnson described Corbyn's position as a "betrayal" of the Brexit vote and a "cynical" and "deluded" attempt to link up with Tory rebels to inflict a damaging defeat on the PM in an upcoming expected vote on a cross-party amendment calling for a customs union.
Corbyn said his call was "consistent" with Labour's position since the referendum, and an "appeal to MPs of all parties" to "put the people's interests before ideological fantasies" to protect jobs, living standards and the economy and avoid a hard Irish border.
His intervention came as the Cabinet prepared for a Thursday meeting where they will finalise the government's position ahead of a major Brexit speech from May on Friday.
While Johnson said the plan would leave Britain as a "colony" of the EU, Corbyn insisted he would not countenance a deal that leaves Britain as a "passive recipient of rules decided elsewhere by others".
On immigration, Corbyn said free movement would end as a "statement of fact" after Brexit and committed to the "reasonable management of migration".
