What is the G7 summit that is coming to Cornwall in June?

The travelling political circus of the G7 that will descend on the rugged shores of Cornwall in June is variously seen as the premier diplomatic event of the year or as a talking shop which causes untold disruption but delivers little of value.

After being becalmed all year by the coronavirus pandemic, the little resort village of Carbis Bay can prepare to be turned upside down by the arrival of at least 10 world leaders, each trailing crowds of advisers, security personnel and media in their wake.

Rings of steel will be erected, whole swathes of the countryside be closed to the public and warships patrol the coast as a thousand TV cameras focus their stare on the likes of Joe Biden, Boris Johnson and Emmanuel Macron gathering for a tete-a-tete in an idyllic setting.

The prime minister has identified the green recovery from pandemic as the focus for the three-day gathering, sandwiched in 2021’s calendar between the rollout of vaccines (which will hopefully by June have begun to tame coronavirus) and the UK’s other international summit in Glasgow in November, when world leaders will discuss measures to tackle climate change.

He also wants to temporarily widen the close-knit G7 circle – the UK, US, Germany, France, Italy, Canada, Japan and the EU – to embrace Australia, India and South Korea in a so-called D10 of democratic nations showing a united front to a world dominated to an increasing extent by authoritarian governments and dictators.

In reality, however, the official agenda for these annual events is almost always overshadowed by the political crisis of the moment, whether a spat between the member states, a financial crash, natural disaster, war or terrorist outrage.

Established in 1975 in the wake of the oil crisis as a cosy “fireside chat” between leaders of six like-minded countries (Canada joined a year later), the G7 has grown exponentially in scale over the years without ever finding a clear direction.

After spending its early years flitting between capitals and major cities (London in 1977, 1984 and 1991, Birmingham in 1998), rioting at the Genoa G7 in 2001 sent host nations in search of ever-more remote locations to keep protests away.

Since then, summits have been held on mountaintops (Kananaskis, Canada in 2002 or Schloss Elmau, Germany in 2015) or in grand countryside hotels and golfing resorts (Gleneagles in Scotland in 2005 and Lough Erne in Northern Ireland in 2013). President Macron all but emptied the elegant seaside resort of Biarritz of its inhabitants in 2019 to give free rein to the delegations and their hangers-on.

Critics say that the differences between members’ agendas – particularly during Russia’s participation in the expanded G8 between 1998 and 2014, before it was expelled over its invasion of Crimea – mean that communiques issued at the end of each summit can never be anything more than bland restatements of support for uncontentious goals like world peace and increased prosperity.

But supporters of the format retort that the very act of voicing consensus in support of global cooperation around goals like democracy, universal education, free trade and sustainable growth provides a valuable counterweight to forces threatening to tear the international order apart.

And there is no doubt that the meetings give leaders a rare opportunity for extended face time to get to know one another personally and exchange ideas.

Talks are typically held in a relatively intimate setting, such as over a small round dining table, without advisers present. Leaders receive simultaneous translation through earpieces from interpreters outside the room, to allow conversation to flow.

When one member does not enter into the convivial mood, like Donald Trump rescinding his signature from the 2018 communique in a row over protectionism, the tension is palpable throughout the venue.

And of course, the guest list around the table changes year on year in a reflection of the ebb and flow of political fortunes.

Longest-serving G7 member Angela Merkel will be attending her 15th and last summit before stepping down as German chancellor in September. As well as Mr Johnson and Mr Biden, Japan’s Yoshihide Suga, European Commission president Ursula von der Leyen and European Council president Charles Michel will be at the table for the first time. And given the current crisis gripping Italy’s government, who can say whether Giuseppe Conte will be prime minister for what would be his third G7?

One thing that is certain is that Mr Johnson will take every opportunity to use his first post-Brexit foray onto the international stage to state the case for his vision of a “global Britain” leading the world in areas like technology, free trade and green growth.

A key measure of the summit’s success will be the extent to which he is able to rehabilitate the UK’s reputation in the eyes of leaders who largely view Brexit not as a springboard to the world but a retreat into nationalistic isolationism.