The PM insisted that the “vast bulk of the work” would be done at Osborne, where he made the announcement at ASC’s Techport hub, suggesting a pre-election mantra with the phrase “Adelaide built, Australian made, Australian jobs, Australian steel”.

“Australia’s future fleet of submarines, 12 regionally superior submarines, will be built here at Osborne in South Australia,” Turnbull said around 11.30am.

“This is securing the future of Australia’s navy for decades to come.

“The submarines project will see Australian workers building Australian submarines with Australian steel – here where we stand today – for decades into the future… 50 years from now submarines will be sustained here, built here, surface vessels will be built here because of the commitment we’ve made to this great national endeavour.”

The emphasis on steel is a nod to Arrium’s embattled Whyalla operation, with today’s announcement – a week out from Budget Day – calculated to cauterise one of the Coalition’s biggest electoral wounds – a perceived lack of support for SA’s flailing manufacturing sector.

Turnbull emphasised that “every dollar we spend on defence procurement as far as possible should be spent in Australia”, but conceded there would be a need to source technology from elsewhere.

“The vast bulk of the work will be done here [in SA, but] there will be constructors across the country, components that will be sourced… combat systems, for example, will be sourced from our friends in the US,” he said.

He thanked the unsuccessful bidders, Germany’s thyssenkrupp Marine Systems (tkMS) and the Japanese Government, for their proposals “which were of a very high quality”.

“However, the recommendation of our competitive evaluation process was unequivocal… the French offer represented the capabilities best able to meet Australia’s operational needs,” Turnbull said.

Politicians were this morning lining up to bask in the reflected light of the announcement, which is expected to see a jobs boon for the defence sector in South Australia, with Turnbull suggesting 2800 jobs would flow nationally from the deal – 1100 safeguarded in SA shipyards and a further 1700 created through the supply chain.

“The spin-offs into the rest of the economy will be immense,” he said.

The SA Cabinet watching the historic announcement that 12 future Submarines will be built & sustained in Adelaide. pic.twitter.com/UE93E1wYjO

— Tom Koutsantonis MP (@TKoutsantonisMP) April 26, 2016

Premier Jay Weatherill was keen to remind South Australians of his Government’s role in the PR offensive that saw off an overseas Japanese build – understood to have been the preferred option of the Abbott administration.

“We were a couple of days away from an overseas Japanese build – it was absolutely done,” Weatherill said.

“We’ve always had to fight for our economic future here in SA,” he told ABC 891, noting: “Victory has many authors.”

“I’m sure many people will be claiming credit.”

Opposition Leader Steven Marshall agreed, saying: “I believe there was a time we weren’t maximising the amount of jobs coming to SA [but] we all put our shoulder to the wheel”.

Confirmed: SA to build 12 new subs with French company @DCNSgroup. Great news @TurnbullMalcolm and great news for local jobs #saparli

— Steven Marshall (@marshall_steven) April 26, 2016

Marshall said all sides of politics needed to work together “to capture every single job”.

“This project will be a great catalyst,” he said.

But Independent Senator Nick Xenophon – whose party has been a chief electoral beneficiary of the subs uncertainty – warned “the devil will be in the detail”.

“Obviously it’s a welcome announcement, but the details aren’t clear as to whether sustainment will still be here, when the work will start, whether the hulls will be built in SA or not,” he told InDaily.

He, like Weatherill, emphasised that before a concerted political campaign the subs were “certain to go to Japan” and “we’re now in a much better position than we were”.

Labor Senator for South Australia Penny Wong said there remained “wriggle room in today’s announcement” and called on Turnbull to rule out a “hybrid build” of the submarines.

She said “the South Australian community” was responsible for today’s announcement because it had “stood up together that Malcolm Turnbull and the Liberal Party have finally done the right thing”.

“The Liberal party have spent three years trying to do everything but the right thing.”

“But there’s a lot more detail to unlock, and I’m looking forward to those details,” he said.

Defence Teaming Centre CEO Chris Burns told reporters in Adelaide this afternoon: “At last we now have certainty about what will be built when and where into the future”.

“Submarines are the most critical piece of military hardware a nation has – particularly an island nation like Australia.

“It’s good to see the Government express its faith in the Australian ship building and sub building industry.”

He said the most immediate task for the industries was to develop the skilled workforce necessary to deliver, requiring some workers to travel to France to learn their building and design methods, and requiring many to gain new qualifications.

Labor MP Nick Champion said he had spoken to Holden workers this morning, who said they were keen for retraining to work on the subs build.

He said because of the time it took for the Government to announce an Australian build, “we’re behind the eightball  … in terms of allowing people to retrain and get re-employed as the automotive industry winds down in 2017”.

ASC’s interim CEO Stuart Whiley said the decision recognised the Government-owned builder’s “highly skilled workforce and recent productivity improvements”.

“ASC has more than 2,600 men and women currently working on submarines and warships; it’s the largest and most capable naval shipbuilding workforce in Australia and the quality of their work is world-class,” he said.

“I congratulate the thousands of workers and suppliers whose commitment to innovation and continuous improvement on our Collins Class program has been a major factor in giving the Government confidence to build the future submarine fleet in Australia.

“ASC is committed to working collaboratively with DCNS from the earliest stages and sharing our unique understanding of Australian submarine requirements and conditions to ensure we build on Australia’s sovereign submarine capability to meet future needs.”

Thyssenkrupp Marine Systems says while it’s disappointed it will not build the $50 billion project in Adelaide, it still stands ready to contribute to Australia’s naval capacities.

“The competitive evaluation was conducted with high integrity and professionalism and we were privileged to be part of it. We are naturally disappointed, but we stand ready to provide support for Australia’s Future Submarines project with our unrivalled experience, leading technology and track record,” the company said in a statement.

But the Japanese Government said the decision was “deeply regrettable”, with Defence Minister Gen Nakatani calling on Australia to explain its decision.

“We will ask Australia to explain why they didn’t pick our design,” he said.

Workers, however, were celebrating the announcement.

Electrician Damien De Wit said like many of his colleagues he had doubts about the prospect of the work coming to SA but the “government had come through in the end”.

“It’s great news for South Australia, great news for all our jobs here and great news for our families,” Mr De Wit told reporters.

“Everyone was asking us what was going on down here and we had no answers.

“Now we do it’s a big relief.”

-with Bension Siebert, AAP and Reuters