The leaders of the 53 Commonwealth countries decided on Friday that Britain's Prince Charles, 69, will be the next head of the Commonwealth, succeeding his mother Queen Elizabeth.
In a statement after their meeting at Windsor Castle, they said: "We recognise the role of the Queen in championing the Commonwealth and its peoples. The next head of the Commonwealth shall be His Royal Highness Prince Charles, the Prince of Wales."
Some have suggested that the role, which is not hereditary, could be rotated around the 53 member states, but the Queen, 92, expressed her preference on Thursday for her oldest child to take it on.
This year's Commonwealth Heads of Government Meeting (Chogm) is likely to be the last that the Queen will attend, as she has cut back on long-haul travel. The next instalment of the biennial gathering will be held in Rwanda.
The selection of a new head was among topics discussed at the leaders-only retreat on Friday, during which they also came to a consensus on issues ranging from boosting trade to protecting the ocean and tackling cybercrime.
With the multilateral trading system under threat as the political mood changes in countries around the world, the group also committed to increasing trade within the Commonwealth to US$2 trillion (S$2.6 trillion) by 2030.
Foreign Minister Vivian Balakrishnan, in an interview with the BBC World Service on the sidelines of Chogm, said on Friday that free trade has been blamed for many of the problems around the world, though the changes are being wrought not by trade but by the new digital revolution.
In such a political zeitgeist, he said, political leaders should give their citizens the confidence that "the governments will provide the training, the education, the skills, the investments in infrastructure needed to cope with this new revolution".
Prime Minister Lee Hsien Loong had said during a roundtable meeting with fellow leaders that Commonwealth countries should make the most of the network, which has functioned as a trade bloc.
In an interview about the two-day meeting with the Singapore media before leaving for home, Mr Lee said the meetings and discussions had been very valuable, particularly for a small country like Singapore "trying to navigate our way forward in a very dangerous world".
He added: "This is a valuable constituency. By coming to the Commonwealth, we have the chance to talk to them, to renew the relationship with them and to strengthen our position in the world."
He also said there were many areas such as in innovation and cyber security which the Commonwealth and Asean could work on together, and that Singapore, as Asean chair this year, would be pursuing these opportunities.
The Commonwealth, a voluntary organisation formed in 1949, is made up of nations with past links to the British Empire - ranging from giant India to the small Pacific nation of Nauru.
At a press conference wrapping up the meeting, British Prime Minister Theresa May said Commonwealth countries, which represent 2.4 billion people, are in a unique position to tackle global problems.
"For when many of the greater challenges we face are global in nature, the breadth of the Commonwealth, spanning six continents and a third of the world's population, offers a unique perspective in helping to forge the global solutions we need," she said.
An estimated 5,000 delegates were in London for Chogm this year.