In addition to the $4 billion reportedly already spent on the now redundant French-Australian joint venture, it is understood taxpayers will have to stump up at least $450 million in contract cancellation fees. It is the Seasprite helicopter debacle all over again, but on a much larger scale.

That said, given the budget blowouts and project delays that have plagued the program since its inception, it does make sense to close it down if a more viable alternative is available than to continue throwing good money after bad.

What we don't know at this stage is if the joint project announced by Prime Ministers Morrison, Prime Minister Johnson and President Biden on Thursday will deliver operational submarines sooner and at less cost. If, as Anthony Albanese has said, the first boat won't be ready until 2040, it is going to be a long wait. The first Attack-class boats were expected to come into service in the early 2030s.

While, as was only to be expected, the French government and its state-owned Naval Group have not taken the news well, they have been the authors of their own misfortunes.

Mr Morrison put the French on notice to get the troubled program, the most expensive defence spend in Australian history, back on track during candid talks with President Macron in June .

Naval Group was given until the start of this month to revise its design work plans for the next two years. Its original plan, submitted in February, was rejected as too expensive.

The anticipated cost of building 12 Australian submarines had blown out from $60 billion to $90 billion in just five years. This was at a time when the French government was telling taxpayers it could build five nuclear-powered Barracudas, the design on which the Attack class is based, for less than $14 billion.

Mr Albanese and South Australian senator Rex Patrick are right to call for transparency on how the Naval Group venture went so bad so quickly and why so much money has been squandered on an aborted white elephant.

Questions about the Attack class debacle should not be allowed to overshadow what is a watershed in the history of Australia and the region, however. America has only shared its nuclear submarine technology once before. That was with the UK in 1958.

The AUKUS agreement which made the deal possible is a direct response to the rise of China. It comes at a time when some had been questioning the strength and value of the US alliance. Given some commentators are seeing this as America's response to Australia being bullied by China, those questions appear to have been answered.

While Beijing's response to what it will see as further proof of encirclement by Western powers is highly predictable, the way the rest of the region, particularly rising powers such as Indonesia, reacts will be significant.

And, although the PM said there is no intention to develop a civil nuclear capacity, we have crossed a nuclear threshold.

It's only a matter of time, given nuclear submarines are likely to be berthing in Brisbane, Sydney, Adelaide, and Perth, before questions are asked about using emissions-free atomic energy rather than gas generators to build resilience into the power grid.

This, despite the knee-jerk reaction Thursday's announcement is sure to provoke, is a legitimate question. Australia is the most sparsely populated country on Earth. It also has massive uranium reserves. This is a debate we should be prepared to have.

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