French President Emmanuel Macron was left furious last week after Australia ditched a mega-deal to buy diesel submarines from France in favour of nuclear-powered US ones, under an agreement secured during secret talks facilitated by Britain.

British Prime Minister Boris Johnson reached out to Macron for a telephone call Friday after Paris accused its UK, US and Australian allies of a "stab in the back" over the deal and dismissed London as a "junior partner" to Washington.

Johnson and Macron "reaffirmed the importance of the UK-France relationship and agreed to continue working closely together around the world on our shared agenda, through NATO and bilaterally," Downing Street said in a statement.

They also noted the "strategic significance" of UK-French cooperation in the Indo-Pacific and in sub-Saharan Africa, it said.

They agreed to "intensify cooperation" against cross-Channel people-smugglers, and to stay in contact over post-Brexit fisheries licences and trading arrangements for Northern Ireland.

The contract for nuclear submarines that sparked the diplomatic crisis forms the centrepiece of a new strategic alliance involving Australia, Britain and the United States known as AUKUS, which is widely seen as an attempt to counter China in the Indo-Pacific.

France and other NATO allies are not in the mix, although the AUKUS trio have stressed it is not meant to be exclusionary.

In a terse account of the Johnson call, Macron's office said the prime minister offered to "re-establish cooperation" and that the French president was "awaiting his proposals".

Macron was more emollient after phone talks on Wednesday with US President Joe Biden.

According to a joint statement, Macron and Biden vowed to meet in Europe at the end of October, prior to both visiting Scotland for a UN climate summit hosted by Johnson.

Downing Street said Johnson "looked forward to welcoming President Macron to Glasgow in November for COP26", with both agreeing on the need for stronger climate action.

- French 'shock' -

Speaking at a meeting of the "E12" European security group, which includes Britain, French Defence Minister Florence Parly said news of the AUKUS alliance had come as a "shock".

"We expect clarification from not only an EI2 member but also an ally and a European country," she told reporters at the talks in Stockholm.

French anger over the submarine contract saw Macron recall the French ambassadors to Washington and Canberra in an unprecedented diplomatic protest.

But the French envoy in London remained at her post, with France's Europe Minister Clement Beaune dismissing London as a mere "third wheel" in the deal.

Using franglais, Johnson this week appealed to France to "donnez-moi un break" while also telling Paris to "prenez un grip" ("get a grip").

The submarine spat has sunk relations between Paris and London to their lowest ebb since Britain's 2016 vote to leave the European Union.

Brexit has led to several disagreements between both nations, notably over fishing rights but also the issue of trade between mainland Britain and Northern Ireland, which came to a head during the G7 leaders' meeting in June.

People-smuggling has also been a major irritant, with UK politicians accusing the French of failing to do more to stem boatloads of migrants crossing the Channel.

There remains, however, a willingness on both sides to continue close cooperation in defence matters, experts say.

The submarine deal "created a legitimate anger in France and clearly dealt a serious blow to trust and cooperation between France and the UK in a relationship already strained by years of post-Brexit disputes", said Hans Kundnani and Alice Billon-Galland, analysts at the Chatham House policy institute.

But they said "the reality is the two countries share a similar set of interests and partners in the Indo-Pacific and beyond, and will need to find ways to navigate current tensions".

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