A former Australian defence minister has told MPs that a key purpose of the Aukus defence pact was to tie Britain into the Indo-Pacific region at a time when Canberra is “in the midst of a tense relationship with China”. Christopher Pyne, who held the post until 2019, told the UK’s defence select committee he believed the initial importance of the Australia-UK-US tie-up announced last week was in the messages it sent to Beijing. “It really formalises the idea of the UK being interested in the Indo-Pacific beyond mere rhetoric,” the former minister said, noting Britain had been gradually retreating from the region in the long aftermath of decolonisation. “Britain’s always had an interest in the Indo-Pacific from a military and foreign policy point of view and lots of friends here. Aukus kind of puts a structure around that, which I think very important to Australia, to the US and the UK,” he added. Western concern about China’s assertiveness helped prompt the formation of Aukus, whose initial task will be to share British and American nuclear-powered submarine technology with Canberra, in a surprise partnership agreement announced by the three countries’ leaders last week. “The fact that Australia has felt that they can do that in the midst of a tense relationship with China sends a very important signal to the Chinese government and Beijing,” Pyne argued. “Putting the screws, if you like, on Australia from an economic and trade point of view has had almost precisely the opposite effect.” Last week, the British prime minister, Boris Johnson, was pressed by his predecessor Theresa May as to whether the UK could get drawn into any future conflict “should China attempt to invade Taiwan” as a result of commitments made in signing the Aukus pact. In reply, Johnson did not rule anything out. The pact’s announcement prompted criticism from Beijing and also intense irritation in Paris. A French contractor was supplying Australia with a new diesel-powered submarine upgrade in a A$90bn (£48bn) deal, until Canberra suddenly cancelled the agreement in favour of the Anglo-American nuclear powered alternative. At the heart of France’s complaints was the fact that it had almost no notice of the cancellation of the contract, being told only about an hour in advance by the Australians, giving Paris no time to respond or propose alternatives. Another witness to the committee suggested Japan was told of the Aukus deal before France. Prof Tetsuo Kotani, a foreign policy expert and senior fellow of Japan Institute of International Affairs, told MPs that “the Japanese government was notified, only one day before the announcement”. Pressed further, Kotani backtracked a little: “My remarks reflect my private conversation with a Japanese government official, so I don’t think it’s a government official stance.” He said he needed to be cautious about claiming Tokyo knew before Paris, suggesting “maybe there was a problem with time difference”.