Though it may come as a surprise listening to Prime Ministers, who routinely refer to one another as “allies”, Britain and Australia are actually only partners – not bound to come together as treaty allies but only informally. This needs correcting.

Let’s begin with why it’s necessary. The new AUKUS pact. Simply put, transferring bits of the nuclear crown jewels – even under the same Queen – requires it. As has been speculated, under the new deal involving Australia, the United Kingdom and the United States, should Britain be the key AUKUS party which transfers critical nuclear propulsion technology to Australia to build nuclear submarines this will have to be codified in a treaty. The Five Powers Defence Arrangements with the UK, Singapore, Malaysia and New Zealand, with its prevision only to consult and not to coordinate the in event of an attack, is not consisted a treaty alliance ­– but just that, an arrangement.

Now there’s the potential. Britain and Australia are approaching a natural defence industrial fit, which hasn’t always been there. Both are building the same British-designed class of frigates. Both fly F-35 fighters, P8 patrol aircraft and soon E7 surveillance jets. Both are trying to develop more sovereign space capacities to supplement the US on relatively constrained budgets.

Not only does AUKUS bring this closer together it opens the door to a new generation of even more ambitious projects. These could include a joint order for a new nuclear submarine fleet to replace the Astute class: smaller, cheaper and potentially faster to produce than what the United States can offer. This could involve a joint order for new satellites, mooted since Brexit, or even space-based weaponry, given the orbital arms race.

It is worth remembering, when planning contingencies, as the birth of AUKUS as a UK-Australia initiative shows, that Canberra will always have more influence and be treated with greater sentiment in London than Washington.

All this needs binding. AUKUS, for all its noise, is still just an agreement. Despite the long time horizons of the submarine order, it is in Australia’s strategic interest for it to start to become reality as soon as possible. The fastest way for it to take physical manifestation could include co-crewing and training on British submarines, and, as it is likely to do for the Americans, Australia should open up basing rights to British submarines. Not only will this enable faster learning for Australia, it will be a physical manifestation of the UK’s Indo-Pacific tilt – a small, but still real, balancing contribution when it comes to China.

All this needs to be bound for the long-term – as tightly as possible. At its core AUKUS is a multi-decade project to deliver nuclear submarines. But both the United States and the United Kingdom are not risk free partners for Australia. In Washington, the political risk is twofold: first is the reelection of Donald Trump or another “America Firster,” with all its ensuing paralysis and instability; second, which cannot be discounted, there is the potential for a political inheritor of the mantle of Bernie Sanders committed to cutting the defence – and with it the submarine – budget.

Meanwhile, in the United Kingdom, the Indo-Pacific tilt has come to be highly associated with the Conservative Party. It should be noted that though this does not speak for the post-Corbyn party leadership, at their most recent conference Labour Party members voted against AUKUS, backing a motion that called it “a dangerous move that will endanger world peace”. The Labour left’s long standing opposition to the UK’s nuclear deterrent and the possible need for it to be relocated in the event of Scottish independence – at very high cost – are also present.

Australia needs both partners and not be too dependent on either. Launching new military industrial projects with London will allow Canberra to offset over-dependence on Washington. Seeking to bind future progressive governments in London to the full delivery of AUKUS through a treaty is sensible diplomatic insurance.

Meanwhile, it is worth remembering, when planning contingencies, as the birth of AUKUS as a UK-Australia initiative shows, that Canberra will always have more influence and be treated with greater sentiment in London than Washington. A treaty helps maintain this for the long term.

Australia’s Scott Morrison (left) and the UK’s Boris Johnson at 10 Downing Street in June (Andrew Parsons/No 10 Downing Street/Flickr)

Due to its NATO commitments, the United Kingdom cannot promise to dispatch a taskforce to Australia’s aid in a conflict with China; neither can Australia dispatch a division for one against Russia. So to avoid over promising and under delivering, the pursuit of a weak NATO Article 5-like commitment would likely stir political flusters with no reward.

This is not the only way to write a treaty, however. A realistic commitment, to consult and coordinate in the event of an attack, would have a binding effect of making the UK and Australia treaty allies and be understood to mean fulsome diplomatic, intelligence, financial and material support in a conflict without overcommitting the other party.

What are the next steps? London and Canberra should commit to update the 2013 UK-Australia Treaty for Defence and Security Cooperation in a way that meets what is necessary, unlocks real potential and is binding. First, this text should be expanded and updated to include AUKUS nuclear cooperation. Second, the text should structure new military-industrial endeavours.

Third, a new conclusion should be added, on common values and the need to consult and coordinate in an attack. This is light language but it nevertheless makes the country’s treaty allies.

It is not “looking for Asian security in London” to sign such a new treaty with Britain. The risk of diplomatic or even military isolation, due to American instability and Chinese aggression makes the multiplication of treaties attractive. The United Kingdom is simply the easiest country to conclude a treaty with before seeking new ones – to consult and coordinate – with Japan, Canada and when hurt eventually recedes, France. Politically, the world assumes the countries already are – allies.

The political opening after AUKUS and the bonhomie between Boris Johnson and Scott Morrison means this should be a priority now. Politically, this can actually get done and fast. Covid-permitting, the British Foreign Secretary should be planning his trip to Canberra to make real allies out of partners.