The former Australian prime minister who signed the now-cancelled French submarine deal has questioned whether Australia could safely maintain a fleet powered by US nuclear technology.

Malcolm Turnbull made the £48 billion deal in 2016 with French majority state-owned Naval Group to build 12 conventional diesel-electric submarines.

Prime Minister Scott Morrison, who replaced Turnbull in a power struggle within Australia’s conservative government in 2018, cancelled the deal this month as part of an alliance with the United States and Britain that will deliver an Australian fleet of at least eight nuclear-powered submarines.

Morrison explained that the “game changer” was that next-generation nuclear-powered submarines will use reactors that do not need refuelling during the 35-year life of the boat.

Turnbull told the National Press Club on Wednesday that he had been advised by the Australia’s Defence Department as recently as 2018 that an Australian nuclear-powered fleet was not an option without local nuclear facilities.

Morrison’s advice that Australia could become the first country to operate a nuclear-powered fleet without a civil nuclear industry or nuclear expertise was “very different” to Defence Department advice three years ago, Turnbull said.

“It sounds too good to be true,” Turnbull said. “Is it credible to have a hands-off, plug-and-play nuclear reactor filled with weapons-grade uranium and not inspect it for 35 years?” he asked.

Turnbull said a nuclear-powered fleet maintained by another country was not an option for Australia.

“If you can’t maintain your own ships, you are not in full control of them,” Turnbull said.

France has accused the United States and Australia of betrayal over the cancelled contract and the replacement trilateral alliance negotiated in secret.

France briefly recalled its ambassador from Washington in protest but there is no word of when a French ambassador might return to Australia.

Turnbull, who describes himself as a personal friend of French president Emmanuel Macron, said Morrison should have discussed with the French Australia’s concerns that conventional submarines would not meet its evolving security needs.

“This is an appalling episode in Australia’s international affairs and the consequences of it will endure to our disadvantage for a very long time,” Turnbull said.

Former prime ministers Paul Keating and Kevin Rudd, who led the centre-left Labor Party, have also been vocal critics of the nuclear deal.

Atomic energy is a fraught issue in Australia, which has a single reactor in Sydney that makes nuclear isotopes for medical use.

Nuclear power generation is banned and Australia refuses to export uranium to countries that would put it to military uses including nuclear propulsion.