On the agenda of the 39th annual summit is the Syrian crisis, breaking down barriers to trade, particularly between Europe and the United States, and curbing global tax avoidance.
Some of those round the small table British Prime Minister David Cameron has ordered for the cosy two-day summit are old hands and have met many times before - the European Commission's Jose Manuel Barroso, Vladimir Putin, Angela Merkel. Others, such as Italy's Prime Minister Enrico Letta and Japan's Shinzo Abe, are new to the stage.
Mr Cameron is expected to meet Mr Obama this morning for talks, and then Mrs Merkel and Mr Hollande this afternoon. All the leaders will arrive in the afternoon for a reception with Northern Ireland secretary Theresa Villiers and Northern Ireland first minister Peter Robinson. In the late afternoon the first formal talks on the global economy will take place, followed by a working dinner to discuss foreign policy - and in particular, Syria.
What does each statesman want? Who are their friends and rivals around the table? And, as they can only sit and watch as fast-growing, debt-light economies overtake them, how long can they claim to be the top table?
Leader: David Cameron (elected May 2010)
This is British Prime Minister David Cameron's chance to shine on the world stage. It is a role he plays particularly well, not least because he is young, telegenic and has an impressive mastery of his brief.
Mr Cameron, as premier of the G8 host, has deliberately tried to make this meeting of the most developed nations a stripped down, business-like affair.
The wives and partners of the other leaders have been excluded to make sure there are no distractions while the leaders attempt to make headway on a range of issues from tax avoidance to the Syrian civil war.
Syria will dominate, with a series of tete a tetes with President Barack Obama and Russian President Vladimir Putin absolutely crucial in the build up to the crucial evening discussion session on foreign policy Monday. This morning he described the summit as a 'peace conference'.
By then Mr Cameron will have hoped to have persuaded Bermuda to join other crown dependencies and territories and agree new terms on tax transparency. He will also be hoping for some sort of global agreement on when to pay ransoms to terrorists.
There is none of the stardust of the last time the G8 was held in Britain in July 2005 – and one of Downing Street’s targets is to keep the cost of this year’s G8 below the £12million cost of that event.
But these are different times. Mr Cameron knows that and he is hoping that without the hype, real progress can be made.
Leader: President François Hollande (elected May 2012)
On trade, François Hollande will be in the comfortable and pleasing position of deciding whether the Prime Minister’s G8 summit is a triumph or a humiliation.
The French President is no political friend to David Cameron and on the issue of transatlantic trade he has it in his gift to decide whether the Lough Erne meeting is a success or failure.
It is unlikely that President Hollande can look the gift horse, of blocking Anglo-Saxon trade liberalism, in the mouth given his opportunity to stand up for the European social model and French “exceptionalism”.
“He can say Non and pose as the defender of France and European social protections against the juggernaut of globalisation. By setting such high expectations on trade, Cameron has walked into a trap,” said an EU diplomat.
France has a veto over an EU negotiating mandate on transatlantic trade because Mr Cameron has pushed for a deal with, as he put it, “everything on the table, even the difficult issues, and no exceptions”.
By going for an inclusive deal, known as a “mixed agreement” in trade negotiating jargon, France has threatened to use its veto to block the proposed trade talks unless cultural sectors, such as television and radio are completely excluded from the agreement.
The French “cultural exception” is an immediate test case for EU red lines on trade talks with many southern European countries also keen to stress their reservations over “Anglo-Saxon economic liberalism”.
Agriculture, a stumbling block for American as well as French farmers, is also on table, an issue that proved indigestible for previous rounds of transatlantic trade talks.
The European Parliament, which must agree any future deal has voiced concerns, said to be shared by the Socialist President over a menu of trade issue ranging from social protection to GM crops.
On Syria, however, Mr Cameron and Mr Hollande will see eye-to-eye. The use of chemical weapons "obliges the international community to act," Mr Hollande said last week. He added: "We can only act within the framework of international law."
Leader: Prime Minister Stephen Harper (elected February 2006)
Canada goes goes into the G8 summit with two major international agreements in its sights.
In the short-term it is in the final stages of negotiations on a free trade agreement with the European Union.
While the talks are far more advanced than the planned EU-US agreement, the two sides have a number of remaining disagreements believed to range from Canadian beef exports to financial services.
Advocates of the agreement had hoped Stephen Harper, the prime minister, might be able to sign while in Europe for the G8 but he warned last month that "a few outstanding issues" made that unlikely.
The Canadians are eager to sign a deal before Europe turns its attention towards the larger negotiations with the United States later this year.
In the long-term, Canada is furiously lobbying the Obama administration to approve the Keystone XL Pipeline, which would carry tar sand oil 2,000 miles from Alberta to Texas. The country's embassy has bought advertising space across Washington in an effort to get its message across.
American green groups are pushing the US president in the other direction, warning the pipeline would be an environmental disaster.
Part of Canada's Keystone negotiation strategy is to hint it could sign an alternative agreement with China if the US refuses to get on board.
The Canadians are also understood be less than enthusiastic about David Cameron's push for a global crackdown on tax avoidance by wealth individuals and multi-national corporations.
The Department of Finance has refused to comment on the issue and critics of Mr Harper suggest that his government is being pushed to obstruct a deal by Canada' big banks.
Government officials privately insist that Canada supports British policy in "broad terms" and it is thought unlikely they would mount a lone opposition to the crackdown, especially if the US gets behind Mr Cameron.
Canada has also emphasised food security and child and maternal health as among its priorities.
Leader: President Barack Obama (elected November 2008)
Trade will top the agenda for the United States, as Barack Obama pushes on two fronts to get the stalled global trade agenda moving again.
Mr Obama has already signaled his clear support for a Transatlantic Trade and Investment Partnership, which is in the early stages of negotiation but already risks getting bogged down by demands for individual exemption by EU member states.
Although British officials are at pains to point out that the G8 is not the official forum for the EU-US trade negotiations, they hope the meeting will give impetus to a process which the White House has said it wants to complete in one package, not in endless rounds of incremental negotiations.
The US-EU deal is matched and mirrored by a US Trans-Pacific Partnership on trade. Both were listed as priorities by Mr Obama in his State of the Union address last February and are seen as twin-track attempt to establish global free trade rules following the failure of the Doha Round.
“The biggest headliner for the US at the G8 is transatlantic trade, no doubt about that,” said Colin Bradford, a former chief economist at the U.S. Agency for International Development and scholar at the Brookings Institution.
“The thinking is that if you get movement on the Transatlantic deal, then the Pacific one moves faster; you set up a competitive dynamic. There is a real sense that the trade agenda needs to move now. If either one of these moves, that will be important news for the global economy.”
Aside from Trade and international tax harmonisation – an issue that has grabbed media attention in the US because of senate hearings over the way Apple pays its taxes – Mr Obama is also expected to use sidelines of the meeting to hold further one-to-one talks with President Putin over Syria. Mr Obama has become convinced of the need to arm the Syrian rebels after tests confirmed the Assad regime had killed at least 150 people with chemical weapons.
“It could be that that is where real news of this summit happens,” added Mr Bradford. “Tax and trade are hugely important but not headline-grabbing issues, and arguably they are really for the G20. It may be that in the future a willingness to tackle security issues is what keeps the G8 grouping relevant.”
Leader: Prime Minister Shinzo Abe (elected December 2012)
It is the first G8 summit for Shinzo Abe, and two issues top his agenda: winning understanding of his government's drastic economic measures and support for security issues in Asia-Pacific.
In return, he is expected to not ruffle any feathers when it comes to David Cameron's three key topics.
Mr Abe will back Britain's position on Syria with verbal support - although Japan will under no circumstances commit military forces or provide logistical support. He will actively back efforts to promote free trade and cracking down on global tax avoidance, both of which could substantially assist Japan.
Mr Abe is trying to fuel Japan's economy with a programme of quantitative easing and large-scale spending. It has added to Japan's national debt which at 238% of GDP is the highest in the developed world.
"For Mr Abe, convincing the rest of the G8 nations of 'Abenomics' is his top priority," said Go Ito, a professor of international relations at Tokyo's Meiji University.
Efforts to reduce the strength of the yen against other major currencies have been a success at home so far, he said, although Japan's partners have expressed concerns that the currency is being manipulated too dramatically.
"Mr Abe will firstly try to calm those fears and explain the positive impact that all the measures that make up 'Abenomics' are having here in Japan," he said.
"Successive Japanese governments have been strongly criticised for the huge national debt and I would expect Mr Abe to emphasise that his government will bring down the debt little by little."
Mr Abe is also likely to use the trip to continue his recent efforts to sell cutting-edge Japanese technology, particularly in the areas of nuclear energy and water purification.
A one-on-one meeting has already been set up with Vladimir Putin,the Russian president, as the Japanese leader attempts to build better ties with Moscow. Mr Abe is hoping to convince Russia to return a group of islands off the far north of Japan that were seized in the dying days of World War II and have prevented the two nations signing a peace treaty ever since. Mr. Abe will also be keen to enlist Russia's support as a bulwark against both an aggressively expansionist China and an unpredictable and nuclear-armed North Korea.
Security will also be the main topic of conversation in another bilateral meeting on the fringes of the main G8 discussions, this one with President Barack Obama. Mr Abe will also want the American leader's verbal support in the ongoing efforts to convince North Korea to return Japanese nationals that were abducted by the regime.
Japan is in favour of a free-trade agreement with Europe, which Tokyo believes will be easier to conclude than the Trans-Pacific Partnership because of the absence of the controversial agricultural sector. Japan is also reluctant to fall behind South Korea in its trading relationship with Europe after Seoul agreed a trade pact with Europe last year.
Efforts to deal with tax avoidance across international boundaries will also win Mr Abe's support as he attempts to get more Japanese companies to stop using overseas tax havens and to contribute more at home.
Leader: President Vladimir Putin (first elected Prime Minister August 1999, President in May 2000)
President Vladimir Putin heads to the G8 summit for the first time in six years at a time of prickly relations between Russia and its western partners, most of all the United States.
Moscow is upset at Washington’s decision in December to introduce the Magnitsky Act - a law banning Russian officials accused of rights abuses from entering the US.
More recently, the Kremlin pounced on the chance to publicly ridicule a bewigged American spy caught in Moscow – and rubbed salt in the wound by revealing the identity of the CIA station chief in the city.
The White House claimed that affair did not buffet relations, and outwardly Mr Putin gets on cordially with US president Barack Obama; but wariness remains on both sides.
The civil war in Syria is likely to dominate the talks at Lough Erne, and Mr Putin - who came back to the Kremlin last year after Dmitry Medvedev’s single term as president - will use bilateral meetings to push Moscow’s line of a negotiated settlement without outside intervention in the conflict.
Russia’s president isimplacably opposed to any suggestion by Mr Cameron that Syrian rebels should be armed, after a UK-France effort lifted a EU weapons embargo. "One should hardly back those who kill their enemies and eat their organs," he said of the rebels at a press conference in London yesterday.
Paramount for Mr Putin is to stall attempts to remove Syria’s President Bashar al-Assad, Moscow’s key ally in the region and the "legitimate" ruler of Syria, while projecting himself as a determined peacemaker.
Prime Minister David Cameron will be hoping to gain Kremlin support for his G8 agenda - boosting trade, cutting tax avoidance and increasing transparency – after a satisfactory meeting with the Russian leader last month at his luxury villa in Sochi on the Black Sea coast.
Mr Putin will at least pay lip service to those ideas, and he and Mr Cameron may build on their agreement in Sochi to a temporary revival of intelligence sharing, six years after it was halted in the wake of the poisoning in London of former KGB officer Alexander Litvinenko.
But Mr Putin will be looking beyond the official agenda to stamp his return to the group of wealthy nations, as Russia prepares to host the G20 summit in St Petersburg in September and assume the rotating chairmanship of the G8 next year.
Leader: Prime Minister Enrico Letta (since 2013)
David Cameron’s plan to use the G8 to call for a lowering of trade barriers and for a war on what he calls the “scourge of tax evasion”, is set to get enthusiastic backing from Italy, which depends on exports and is fighting against chronic tax dodging at home.
“Italy faces the worst tax evasion in the G8, often through the hidden movement of capital, and is penalised by weak coordination of the fight against the phenomenon,” said Marcello Missori, a professor of economics at LUISS university in Rome.
Currently the shrinking Italian economy needs all the help it can get as it stumbles through its second recessionary year, while exports – a traditional mainstay of the economy thanks to the country’s thousands of small and medium sized manufacturers -- dropped 1.9 percent in the first quarter, the first quarterly fall since mid-2009.
“Italy is an open economy where exports are the most dynamic sector and where primary materials are imported,” said Missori. “Anything that cuts tariffs can only help,” he added.
Missori said any gains on tax evasion and trade tariffs made in Northern Ireland could be used by Italy to help jumpstart the vital reform of its red tape bound and inefficient economy back home.
“The Italian government needs to take a really active part in this G8 and use the benefits as a stimulus,” he said.
Leader: Chancellor Angela Merkel (since 2005)
At Angela Merkel’s first G8, at St Petersburg in 2006, the most powerful man in the world greeted the newcomer with an unexpected squeeze between the shoulderblades.
The German chancellor’s disgusted reaction to George Bush’s back rub - she threw her hands into the hair and grimaced - has been preserved for posterity on Youtube.
But, observers say, she rose above the frat-boy treatment to be an assured international player.
“She was always very good,” said Dr Claudia Schmucker, a globalization expert at the German Council on Foreign Relations, a thinktank. “It's scary to be at these summits, but when she was new she was already very self-confident and very good in the negotiations. Always very active - not holding back.”
On the key issues of trade and tax there is common ground between Mrs Merkel and David Cameron, who have a strong personal relationship. Speaking at Davos earlier this year, the German chancellor backed Britain’s plans to use the G8 to lead a debate on tax evasion and tax avoidance.
Both countries support an EU-US free trade agreement, the Transatlantic Trade and Investment Partnership.
“We are very close to the UK on all the G8 issues,” Dr Schmucker said. “On a personal level I think Cameron and Merkel get along really well. They share a lot of values. The Transatlantic Trade and Investment Partnership - they are just in favour of this, they just want this in.”
When it comes to some of the sticking points of the transatlantic deal - such as whether it would lead to the weakening of EU standards on GM food - the stumbling block is France.
Relations between Francois Hollande, the French president, and Mrs Merkel are notoriously frosty.
Dr Schmucker said: “I think there are problematic issues such as GM food - this is where it’s really important to talk to France.
“Germany and the UK have no problem with it. I think they will really put pressure on Hollande to move on some of these issues.”
On Syria, Germany has been sceptical about the Anglo-French initiative to raise the EU’s arms embargo. Along with Austria, Sweden and the Czech Republic, Germany feared the consequences of an influx of weapons to the region.
For Germany, the highlight of this year’s G8 will come at the end. Barack Obama will follow the summit with a visit to Berlin on June 18 and 19, his first trip to the German capital as president. He will hold talks with Mrs Merkel and, next Wednesday, deliver a speech at the Brandenburg Gate.
Despite the two countries’ contrasting views on how to cure the economic slump - the US favours deficit spending while Germany is the lead proponent of austerity - Dr Schmucker described it as a recognition of Berlin’s importance.
“He believes we are the central country to solve the euro crisis. The US is more into spending, but he believes Germany is central to the euro crisis. I think that is why he is coming to us.”
Leader: European Commission President José Manuel Barroso (since November 2004)
David Cameron’s attempt to “pre-cook” a G8 summit triumph on transatlantic free trade is at risk because of deep European Union divisions.
European diplomats and officials have warned that the Prime Minister’s attempts to choreograph an EU-US trade deal may have backfired.
Mr Cameron has pushed the EU into quickly agreeing a “negotiating mandate” before Monday’s G8 meeting at a meeting of Europe’s trade ministers on Friday.
“The British Prime Minister has tried to rush a deal on a mandate so he can stand on a press podium with Obama to take all the credit,” said a European diplomat.
“The danger is he has bungled it, putting back the chances of agreement and putting EU divisions on display at the G8.”
The EU will try and get agreement on a mandate for a Transatlantic Trade and Investment Partnership with the US before the G8 summit, a deal within deal that will be unveiled as a triumph alongside the US president at Lough Erne.
It is risky strategy for Mr Cameron because the mandate is a so-called “mixed agreement” covering politically sensitive areas, such as textiles and agriculture, where national vetoes apply on trade.
To get EU agreement he will need unanimity, handing the trump cards to France and other protectionist European countries that are hostile to “Anglo-Saxon economic liberalism”.
To make it worse for the British leader, he has linked the success of the transatlantic trade talks to a British referendum on EU membership in 2017.
“They will be difficult negotiations, very difficult. The outcome is far from certain,” said an EU trade negotiator.
A successful EU-US trade deal could benefit the average European household by £462 a year in cheaper goods and services, an economic bonanza that would create 400,000 new jobs in Europe.
Such an agreement would be a major factor in a Yes to EU membership campaign in a future British referendum. Failure born out of European divisions would lend weight to the case of Conservatives pushing for Britain to leave.
“An EU-US free trade deal is the holy grail. But like the grail has the qualities of a miracle. The EU has pursued it for decades without success,” said a senior European official.