Tackling climate change and countering violent extremism will top the agenda at the Commonwealth summit in Malta this week, attended by Queen Elizabeth II and French President Francois Hollande.
Coming after the Paris terror attacks this month and just before the COP21 world climate talks hosted in the French capital, the meeting will bring together G20 powers and tiny microstates spanning the continents.
Because the 53-country group contains such diverse countries, the talks are being closely watched in world capitals for signs of agreement on climate change that could herald a deal at the UN COP21 summit.
"It can really help the outcome in Paris," Liz Gallagher, programme leader at the E3G environmental think-tank, told AFP -- even though major powers such as China and the United States are not involved.
The Commonwealth Heads of Government Meeting (CHOGM) begins on Friday and wraps up on Sunday, a day before the COP21 talks start in Paris.
Born out of the British empire, the Commonwealth of Nations brings together around a quarter of the world's countries and a third of its population.
Gallagher said she would be looking out for the organisation's main developed economies -- Australia, Britain and Canada -- "outlining the contours of a support package for the most vulnerable countries".
"This is one of the big sticking points," she said.
"New voices in the negotiations", such as Malaysia and Singapore, as well the views of new leaders in Australia and Canada, will also be of particular interest.
The climate talks will be attended by United Nations Secretary-General Ban Ki-moon and Hollande, who is keen to emphasise the urgency of climate talks -- particularly on newly-elected Canadian Prime Minister Justin Trudeau, officials said.
Queen Elizabeth, the Head of the Commonwealth, will pay a state visit to Malta from Thursday for the summit, accompanied by her husband Prince Philip, their eldest son Prince Charles and his wife Camilla.
"CHOGM is taking place during a critical year when the world determines the path forward on significant global issues," said Commonwealth Secretary-General Kamalesh Sharma.
An indication of its significance is that among the few ideas adopted at the flop 2009 Copenhagen climate talks were those emanating from the preceding CHOGM.
The Commonwealth is now proposing debt for climate action swaps, whereby smaller island states and developing countries could get debt relief in return for action on climate change.
