UK Ambassador Vicki Treadell, left, and Peter Dutton on the right. Credit: Australian Defense Department, Kym Smith

SYDNEY — In a clear signal of just how high the stakes are in the AUKUS quest to allow Australia to build and deploy a small fleet of nuclear attack submarines, the British ambassador recently scolded the Australian leader of the opposition here for criticizing the quality of British boats.

British High Commissioner Vicki Treadell took the rare step of making public a discussion she said she had with minister Peter Dutton last night, just six days before her prime minister is expected to join his Australian counterpart, Anthony Albanese, and President Joe Biden, to announce the details of the AUKUS sub program. The three countries have spent the last 18 months hammering the plan out, including the key question of which nation would supply sub tech to Canberra.

“He is commenting on an outcome he doesn’t yet know,” she said, referring to Dutton’s comments last week praising American subs to the Brits’ expense. “There is a lot of speculation; everyone is entitled to speculate. I was simply pointing out that I did not think such expressions were helpful on what is a genuine trilateral partnership started under his government.”

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Treadell picked perhaps the most public venue possible, the National Press Club of Australia, for her remarks. For those not familiar with the sometimes fraught — but very close — relationship between Australia and its former colonial ruler, Australians often enjoy taking a hard poke at the British. And the inhabitants of the small islands north of France sometimes find satisfaction in referring to the criminal pasts of many early Australian colonists.

Dutton, also former Australian defense minister, had said that American subs were better than those sailing for the UK and should be picked for the Austalian program. He also said Rolls Royce, which does much of the most critical work on the British subs, doesn’t have enough capacity to take on more production. (The company did not respond to Breaking Defense’s request for comment last week.)

“The advice to me at the time was very clear: that Rolls-Royce didn’t have any production capability left, no headroom; Barrow-in-Furness is obviously landlocked, it didn’t have the ability to scale up,” he said last week.

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There’s been persistent but low-level criticism of Britain here for not buying as much Australian defense equipment as Australia buys from Britain. At today’s event, Treadell pushed back on the notion.

“The fact that we are in partnership, not just on a future solution for Australia’s submarine capability, what we are already doing on the Type 26 frigate tells you all you need to know,” she replied. “We are integrating supply chains, we’re at how we develop the skills and capacity in our workforce that we both need. This is a win-win for both countries and America as well.”

She noted that, more broadly, Britain was “Australia’s second-largest source of foreign investment” in 2021. “In return, the UK is the second-largest destination for Australian investment overseas.”

If the rumors are true that Britain will supply a version off its as the model for Australia’s boats, that investment may swell considerably over the next decade. All, or at least some, is expected to become clear on Monday when AUKUS’s three leaders speak from San Diego.