Officials of the Group of 20 leading economies meeting in London on Thursday ahead of next month’s summit are searching for the holy grail to which all summits aspire. These are the “deliverables”, or agreements that can plausibly be presented as a justifiable return for the time, salaries and air miles of the dozens of bureaucrats involved.

But apart from a possible agreement on extra funding for the International Monetary Fund, which was in train before the G20 alighted on it, officials and observers say it may be difficult to translate the grand principles of international co-operation into concrete progress.