Comments made by David Cameron never meant to be heard by the public, let alone the people they were about, have come back to haunt the Prime Minister.
Talking to the Queen, Cameron declared Nigeria and Afghanistan "fantastically corrupt", comments described as "embarrassing" by a spokesman for Nigerian president Muhammadu Buhari and "unfair" by the Afghan embassy in London.
A different spokesman for the president has added further comments from Buhari through his Twitter page.
Asked whether he wanted an apology from Cameron, Buhari told an anti-corruption event hosted by the Commonwealth Secretariat in London: "I am not going to demand any apology from anybody. What I am demanding is the return of assets."
He mentioned Britain's readiness to hand over the "bank account and fixed assets" of a Nigerian governor who died after being accused of money-laundering.
"This is what I'm asking for," said Buhari "What would I do with an apology? I need something tangible."
The Prime Minister has come under increasing pressure from the House of Commons over tax secrecy in Britain's overseas territories and Crown dependencies - but Cameron stood up for developing countries, urging critics to be "fair" to the territories, which he said had shown greater readiness to introduce transparency than many developed countries.
Cameron acknowledged that action on corruption must also be taken by developed countries as well as those in the developing world, and said new rules requiring foreign companies to declare the true owners of property in the UK would help ensure that they are not used as a place to stash "plundered money" from African countries.
After revelations about offshore financial activities in the Panama Papers, Cameron last month announced that the overseas territories and crown dependencies - like the British Virgin Islands and Jersey - had agreed to provide UK tax and law enforcement agencies with full access to company ownership details.
But charities have insisted they must go further and allow public access to registers, so they can be examined by journalists and NGOs, and Cameron was pressed on the issue by Labour leader Jeremy Corbyn and backbench MPs at Prime Minister's Questions.
Cameron said: "We asked three things of the overseas territories and Crown dependencies.
"We asked for automatic exchange of tax information, we asked for a common reporting standard for multinational companies and we asked for central beneficial ownership registries, so UK enforcement could know who really owns companies that are based there.
"They've delivered on the first two and they will be following and delivering on the third."
Scottish National Party Parliamentary Group leader Angus Robertson asked the PM if he had heard appeals from Nigerian anti-corruption activists who said their efforts were "seriously undermined" by the UK allowing corrupt individuals to "hide their ill-gotten gains in your luxury homes, department stores, car dealerships, private schools and anywhere else that will accept their cash with no questions asked".
Robertson said: "The role of London's property market to conceal stolen wealth has been exposed in court documents, reports, documentaries and more. What is the Prime Minister going to do about this?"
Cameron responded: "Action is necessary by developed countries as well as developing countries and the steps we are taking to make sure that foreign companies that own UK property have to declare who the beneficial owner is will be one of the ways we make sure that plundered money from African countries can't be hidden in London."
Writing in The Guardian, former Prime Minister Gordon Brown said: "If we are to ensure no hiding places for tax evaders, no safe haven for tax avoiders and no treasure islands for the money launderers who hide an estimated 7.5 trillion US dollars (£5.2 trillion) of global wealth, we need the automatic exchange of tax information worldwide."
Cameron acknowledged the awkwardness caused by his unflattering remarks about his summit guests, telling MPs that "tips on diplomacy are useful, given the last 24 hours", during which he admitted he had made "many unforced errors".
He said that the leaders of Nigeria and Afghanistan are "battling hard against very corrupt systems" and had made "remarkable steps forward".